refactor(cli/js/ops/fs): Improve readdir() and FileInfo interfaces (#4763)

33 files changed, 307 insertions, 355 deletions

diff --git a/cli/js/deno.ts b/cli/js/deno.ts
index ca323fc95..89795119b 100644
--- a/cli/js/deno.ts
+++ b/cli/js/deno.ts
@@ -23,7 +23,6 @@ export {
 export { chdir, cwd } from "./ops/fs/dir.ts";
 export { applySourceMap, formatDiagnostics } from "./ops/errors.ts";
 export { errors } from "./errors.ts";
-export { FileInfo } from "./file_info.ts";
 export {
   File,
   open,
@@ -97,7 +96,7 @@ export {
 export { openPlugin } from "./plugins.ts";
 export { kill } from "./ops/process.ts";
 export { run, RunOptions, Process, ProcessStatus } from "./process.ts";
-export { readdirSync, readdir } from "./ops/fs/read_dir.ts";
+export { DirEntry, readdirSync, readdir } from "./ops/fs/read_dir.ts";
 export { readFileSync, readFile } from "./read_file.ts";
 export { readlinkSync, readlink } from "./ops/fs/read_link.ts";
 export { realpathSync, realpath } from "./ops/fs/realpath.ts";
@@ -105,7 +104,7 @@ export { removeSync, remove, RemoveOptions } from "./ops/fs/remove.ts";
 export { renameSync, rename } from "./ops/fs/rename.ts";
 export { resources, close } from "./ops/resources.ts";
 export { signal, signals, Signal, SignalStream } from "./signals.ts";
-export { statSync, lstatSync, stat, lstat } from "./ops/fs/stat.ts";
+export { FileInfo, statSync, lstatSync, stat, lstat } from "./ops/fs/stat.ts";
 export { symlinkSync, symlink } from "./ops/fs/symlink.ts";
 export { connectTLS, listenTLS } from "./tls.ts";
 export { truncateSync, truncate } from "./ops/fs/truncate.ts";
diff --git a/cli/js/file_info.ts b/cli/js/file_info.ts
deleted file mode 100644
index 27df0bbb7..000000000
--- a/cli/js/file_info.ts
+++ /dev/null
@@ -1,87 +0,0 @@
-// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-import { StatResponse } from "./ops/fs/stat.ts";
-import { build } from "./build.ts";
-
-export interface FileInfo {
-  size: number;
-  modified: number | null;
-  accessed: number | null;
-  created: number | null;
-  name: string | null;
-  dev: number | null;
-  ino: number | null;
-  mode: number | null;
-  nlink: number | null;
-  uid: number | null;
-  gid: number | null;
-  rdev: number | null;
-  blksize: number | null;
-  blocks: number | null;
-  isFile(): boolean;
-  isDirectory(): boolean;
-  isSymlink(): boolean;
-}
-
-// @internal
-export class FileInfoImpl implements FileInfo {
-  readonly #isFile: boolean;
-  readonly #isDirectory: boolean;
-  readonly #isSymlink: boolean;
-  size: number;
-  modified: number | null;
-  accessed: number | null;
-  created: number | null;
-  name: string | null;
-
-  dev: number | null;
-  ino: number | null;
-  mode: number | null;
-  nlink: number | null;
-  uid: number | null;
-  gid: number | null;
-  rdev: number | null;
-  blksize: number | null;
-  blocks: number | null;
-
-  /* @internal */
-  constructor(res: StatResponse) {
-    const isUnix = build.os === "mac" || build.os === "linux";
-    const modified = res.modified;
-    const accessed = res.accessed;
-    const created = res.created;
-    const name = res.name;
-    // Unix only
-    const { dev, ino, mode, nlink, uid, gid, rdev, blksize, blocks } = res;
-
-    this.#isFile = res.isFile;
-    this.#isDirectory = res.isDirectory;
-    this.#isSymlink = res.isSymlink;
-    this.size = res.size;
-    this.modified = modified ? modified : null;
-    this.accessed = accessed ? accessed : null;
-    this.created = created ? created : null;
-    this.name = name ? name : null;
-    // Only non-null if on Unix
-    this.dev = isUnix ? dev : null;
-    this.ino = isUnix ? ino : null;
-    this.mode = isUnix ? mode : null;
-    this.nlink = isUnix ? nlink : null;
-    this.uid = isUnix ? uid : null;
-    this.gid = isUnix ? gid : null;
-    this.rdev = isUnix ? rdev : null;
-    this.blksize = isUnix ? blksize : null;
-    this.blocks = isUnix ? blocks : null;
-  }
-
-  isFile(): boolean {
-    return this.#isFile;
-  }
-
-  isDirectory(): boolean {
-    return this.#isDirectory;
-  }
-
-  isSymlink(): boolean {
-    return this.#isSymlink;
-  }
-}
diff --git a/cli/js/lib.deno.ns.d.ts b/cli/js/lib.deno.ns.d.ts
index 443952c96..0480d2613 100644
--- a/cli/js/lib.deno.ns.d.ts
+++ b/cli/js/lib.deno.ns.d.ts
@@ -1317,9 +1317,17 @@ declare namespace Deno {
   export function readFile(path: string): Promise<Uint8Array>;
 
   /** A FileInfo describes a file and is returned by `stat`, `lstat`,
-   * `statSync`, `lstatSync`. A list of FileInfo is returned by `readdir`,
-   * `readdirSync`. */
+   * `statSync`, `lstatSync`. */
   export interface FileInfo {
+    /** True if this is info for a regular file. Mutually exclusive to
+     * `FileInfo.isDirectory` and `FileInfo.isSymlink`. */
+    isFile: boolean;
+    /** True if this is info for a regular directory. Mutually exclusive to
+     * `FileInfo.isFile` and `FileInfo.isSymlink`. */
+    isDirectory: boolean;
+    /** True if this is info for a symlink. Mutually exclusive to
+     * `FileInfo.isFile` and `FileInfo.isDirectory`. */
+    isSymlink: boolean;
     /** The size of the file, in bytes. */
     size: number;
     /** The last modification time of the file. This corresponds to the `mtime`
@@ -1334,8 +1342,6 @@ declare namespace Deno {
      * field from `stat` on Mac/BSD and `ftCreationTime` on Windows. This may not
      * be available on all platforms. */
     created: number | null;
-    /** The file or directory name. */
-    name: string | null;
     /** ID of the device containing the file.
      *
      * _Linux/Mac OS only._ */
@@ -1373,15 +1379,6 @@ declare namespace Deno {
      *
      * _Linux/Mac OS only._ */
     blocks: number | null;
-    /** Returns whether this is info for a regular file. This result is mutually
-     * exclusive to `FileInfo.isDirectory` and `FileInfo.isSymlink`. */
-    isFile(): boolean;
-    /** Returns whether this is info for a regular directory. This result is
-     * mutually exclusive to `FileInfo.isFile` and `FileInfo.isSymlink`. */
-    isDirectory(): boolean;
-    /** Returns whether this is info for a symlink. This result is
-     * mutually exclusive to `FileInfo.isFile` and `FileInfo.isDirectory`. */
-    isSymlink(): boolean;
   }
 
   /** Returns absolute normalized path, with symbolic links resolved.
@@ -1408,28 +1405,33 @@ declare namespace Deno {
    * Requires `allow-read` permission. */
   export function realpath(path: string): Promise<string>;
 
-  /** UNSTABLE: This API is likely to change to return an iterable object instead
-   *
-   * Synchronously reads the directory given by `path` and returns an array of
-   * `Deno.FileInfo`.
+  export interface DirEntry extends FileInfo {
+    name: string;
+  }
+
+  /** Synchronously reads the directory given by `path` and returns an iterable
+   * of `Deno.DirEntry`.
    *
-   *       const files = Deno.readdirSync("/");
+   *       for (const dirEntry of Deno.readdirSync("/")) {
+   *         console.log(dirEntry.name);
+   *       }
    *
    * Throws error if `path` is not a directory.
    *
    * Requires `allow-read` permission. */
-  export function readdirSync(path: string): FileInfo[];
+  export function readdirSync(path: string): Iterable<DirEntry>;
 
-  /** UNSTABLE: This API is likely to change to return an `AsyncIterable`.
-   *
-   * Reads the directory given by `path` and resolves to an array of `Deno.FileInfo`.
+  /** Reads the directory given by `path` and returns an async iterable of
+   * `Deno.DirEntry`.
    *
-   *       const files = await Deno.readdir("/");
+   *       for await (const dirEntry of Deno.readdir("/")) {
+   *         console.log(dirEntry.name);
+   *       }
    *
    * Throws error if `path` is not a directory.
    *
    * Requires `allow-read` permission. */
-  export function readdir(path: string): Promise<FileInfo[]>;
+  export function readdir(path: string): AsyncIterable<DirEntry>;
 
   /** Synchronously copies the contents and permissions of one file to another
    * specified path, by default creating a new file if needed, else overwriting.
@@ -1476,7 +1478,7 @@ declare namespace Deno {
    * points to.
    *
    *       const fileInfo = await Deno.lstat("hello.txt");
-   *       assert(fileInfo.isFile());
+   *       assert(fileInfo.isFile);
    *
    * Requires `allow-read` permission. */
   export function lstat(path: string): Promise<FileInfo>;
@@ -1486,7 +1488,7 @@ declare namespace Deno {
    * what it points to..
    *
    *       const fileInfo = Deno.lstatSync("hello.txt");
-   *       assert(fileInfo.isFile());
+   *       assert(fileInfo.isFile);
    *
    * Requires `allow-read` permission. */
   export function lstatSync(path: string): FileInfo;
@@ -1495,7 +1497,7 @@ declare namespace Deno {
    * follow symlinks.
    *
    *       const fileInfo = await Deno.stat("hello.txt");
-   *       assert(fileInfo.isFile());
+   *       assert(fileInfo.isFile);
    *
    * Requires `allow-read` permission. */
   export function stat(path: string): Promise<FileInfo>;
@@ -1504,7 +1506,7 @@ declare namespace Deno {
    * always follow symlinks.
    *
    *       const fileInfo = Deno.statSync("hello.txt");
-   *       assert(fileInfo.isFile());
+   *       assert(fileInfo.isFile);
    *
    * Requires `allow-read` permission. */
   export function statSync(path: string): FileInfo;
diff --git a/cli/js/ops/fs/read_dir.ts b/cli/js/ops/fs/read_dir.ts
index c48104d4b..29b8676ef 100644
--- a/cli/js/ops/fs/read_dir.ts
+++ b/cli/js/ops/fs/read_dir.ts
@@ -1,24 +1,32 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import { sendSync, sendAsync } from "../dispatch_json.ts";
-import { FileInfo, FileInfoImpl } from "../../file_info.ts";
-import { StatResponse } from "./stat.ts";
+import { FileInfo, StatResponse, parseFileInfo } from "./stat.ts";
+
+export interface DirEntry extends FileInfo {
+  name: string;
+}
 
 interface ReadDirResponse {
   entries: StatResponse[];
 }
 
-function res(response: ReadDirResponse): FileInfo[] {
+function res(response: ReadDirResponse): DirEntry[] {
   return response.entries.map(
-    (statRes: StatResponse): FileInfo => {
-      return new FileInfoImpl(statRes);
+    (statRes: StatResponse): DirEntry => {
+      return { ...parseFileInfo(statRes), name: statRes.name! };
     }
   );
 }
 
-export function readdirSync(path: string): FileInfo[] {
-  return res(sendSync("op_read_dir", { path }));
+export function readdirSync(path: string): Iterable<DirEntry> {
+  return res(sendSync("op_read_dir", { path }))[Symbol.iterator]();
 }
 
-export async function readdir(path: string): Promise<FileInfo[]> {
-  return res(await sendAsync("op_read_dir", { path }));
+export function readdir(path: string): AsyncIterable<DirEntry> {
+  const array = sendAsync("op_read_dir", { path }).then(res);
+  return {
+    async *[Symbol.asyncIterator](): AsyncIterableIterator<DirEntry> {
+      yield* await array;
+    },
+  };
 }
diff --git a/cli/js/ops/fs/stat.ts b/cli/js/ops/fs/stat.ts
index 5d8860939..6b7e5ea93 100644
--- a/cli/js/ops/fs/stat.ts
+++ b/cli/js/ops/fs/stat.ts
@@ -1,6 +1,25 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import { sendSync, sendAsync } from "../dispatch_json.ts";
-import { FileInfo, FileInfoImpl } from "../../file_info.ts";
+import { build } from "../../build.ts";
+
+export interface FileInfo {
+  size: number;
+  modified: number | null;
+  accessed: number | null;
+  created: number | null;
+  dev: number | null;
+  ino: number | null;
+  mode: number | null;
+  nlink: number | null;
+  uid: number | null;
+  gid: number | null;
+  rdev: number | null;
+  blksize: number | null;
+  blocks: number | null;
+  isFile: boolean;
+  isDirectory: boolean;
+  isSymlink: boolean;
+}
 
 export interface StatResponse {
   isFile: boolean;
@@ -10,6 +29,7 @@ export interface StatResponse {
   modified: number;
   accessed: number;
   created: number;
+  // Null for stat(), but exists for readdir().
   name: string | null;
   // Unix only members
   dev: number;
@@ -23,12 +43,36 @@ export interface StatResponse {
   blocks: number;
 }
 
+// @internal
+export function parseFileInfo(response: StatResponse): FileInfo {
+  const isUnix = build.os === "mac" || build.os === "linux";
+  return {
+    isFile: response.isFile,
+    isDirectory: response.isDirectory,
+    isSymlink: response.isSymlink,
+    size: response.size,
+    modified: response.modified ? response.modified : null,
+    accessed: response.accessed ? response.accessed : null,
+    created: response.created ? response.created : null,
+    // Only non-null if on Unix
+    dev: isUnix ? response.dev : null,
+    ino: isUnix ? response.ino : null,
+    mode: isUnix ? response.mode : null,
+    nlink: isUnix ? response.nlink : null,
+    uid: isUnix ? response.uid : null,
+    gid: isUnix ? response.gid : null,
+    rdev: isUnix ? response.rdev : null,
+    blksize: isUnix ? response.blksize : null,
+    blocks: isUnix ? response.blocks : null,
+  };
+}
+
 export async function lstat(path: string): Promise<FileInfo> {
   const res = (await sendAsync("op_stat", {
     path,
     lstat: true,
   })) as StatResponse;
-  return new FileInfoImpl(res);
+  return parseFileInfo(res);
 }
 
 export function lstatSync(path: string): FileInfo {
@@ -36,7 +80,7 @@ export function lstatSync(path: string): FileInfo {
     path,
     lstat: true,
   }) as StatResponse;
-  return new FileInfoImpl(res);
+  return parseFileInfo(res);
 }
 
 export async function stat(path: string): Promise<FileInfo> {
@@ -44,7 +88,7 @@ export async function stat(path: string): Promise<FileInfo> {
     path,
     lstat: false,
   })) as StatResponse;
-  return new FileInfoImpl(res);
+  return parseFileInfo(res);
 }
 
 export function statSync(path: string): FileInfo {
@@ -52,5 +96,5 @@ export function statSync(path: string): FileInfo {
     path,
     lstat: false,
   }) as StatResponse;
-  return new FileInfoImpl(res);
+  return parseFileInfo(res);
 }
diff --git a/cli/js/tests/files_test.ts b/cli/js/tests/files_test.ts
index f81ed3c47..1f7352afc 100644
--- a/cli/js/tests/files_test.ts
+++ b/cli/js/tests/files_test.ts
@@ -273,7 +273,7 @@ unitTest(
     const filename = tempDir + "/test.txt";
     const f = await Deno.create(filename);
     let fileInfo = Deno.statSync(filename);
-    assert(fileInfo.isFile());
+    assert(fileInfo.isFile);
     assert(fileInfo.size === 0);
     const enc = new TextEncoder();
     const data = enc.encode("Hello");
@@ -297,7 +297,7 @@ unitTest(
     let file = await Deno.open(filename, "w");
     // assert file was created
     let fileInfo = Deno.statSync(filename);
-    assert(fileInfo.isFile());
+    assert(fileInfo.isFile);
     assertEquals(fileInfo.size, 0);
     // write some data
     await file.write(data);
@@ -335,7 +335,7 @@ unitTest(
     const seekPosition = 0;
     // assert file was created
     let fileInfo = Deno.statSync(filename);
-    assert(fileInfo.isFile());
+    assert(fileInfo.isFile);
     assertEquals(fileInfo.size, 0);
     // write some data
     await file.write(data);
diff --git a/cli/js/tests/link_test.ts b/cli/js/tests/link_test.ts
index e9f72ebef..c6ea4901e 100644
--- a/cli/js/tests/link_test.ts
+++ b/cli/js/tests/link_test.ts
@@ -31,8 +31,8 @@ unitTest(
     // Remove oldname. File still accessible through newname.
     Deno.removeSync(oldName);
     const newNameStat = Deno.statSync(newName);
-    assert(newNameStat.isFile());
-    assert(!newNameStat.isSymlink()); // Not a symlink.
+    assert(newNameStat.isFile);
+    assert(!newNameStat.isSymlink); // Not a symlink.
     assertEquals(
       newData3,
       new TextDecoder().decode(Deno.readFileSync(newName))
@@ -137,8 +137,8 @@ unitTest(
     // Remove oldname. File still accessible through newname.
     Deno.removeSync(oldName);
     const newNameStat = Deno.statSync(newName);
-    assert(newNameStat.isFile());
-    assert(!newNameStat.isSymlink()); // Not a symlink.
+    assert(newNameStat.isFile);
+    assert(!newNameStat.isSymlink); // Not a symlink.
     assertEquals(
       newData3,
       new TextDecoder().decode(Deno.readFileSync(newName))
diff --git a/cli/js/tests/mkdir_test.ts b/cli/js/tests/mkdir_test.ts
index 5823d6e38..20120f6b3 100644
--- a/cli/js/tests/mkdir_test.ts
+++ b/cli/js/tests/mkdir_test.ts
@@ -3,7 +3,7 @@ import { unitTest, assert, assertEquals, assertThrows } from "./test_util.ts";
 
 function assertDirectory(path: string, mode?: number): void {
   const info = Deno.lstatSync(path);
-  assert(info.isDirectory());
+  assert(info.isDirectory);
   if (Deno.build.os !== "win" && mode !== undefined) {
     assertEquals(info.mode! & 0o777, mode & ~Deno.umask());
   }
diff --git a/cli/js/tests/read_dir_test.ts b/cli/js/tests/read_dir_test.ts
index 95936c645..2c7f42103 100644
--- a/cli/js/tests/read_dir_test.ts
+++ b/cli/js/tests/read_dir_test.ts
@@ -1,14 +1,12 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import { unitTest, assert, assertEquals } from "./test_util.ts";
 
-type FileInfo = Deno.FileInfo;
-
-function assertSameContent(files: FileInfo[]): void {
+function assertSameContent(files: Deno.DirEntry[]): void {
   let counter = 0;
 
   for (const file of files) {
     if (file.name === "subdir") {
-      assert(file.isDirectory());
+      assert(file.isDirectory);
       counter++;
     }
 
@@ -22,7 +20,7 @@ function assertSameContent(files: FileInfo[]): void {
 }
 
 unitTest({ perms: { read: true } }, function readdirSyncSuccess(): void {
-  const files = Deno.readdirSync("cli/tests/");
+  const files = [...Deno.readdirSync("cli/tests/")];
   assertSameContent(files);
 });
 
@@ -68,7 +66,10 @@ unitTest({ perms: { read: true } }, function readdirSyncNotFound(): void {
 unitTest({ perms: { read: true } }, async function readdirSuccess(): Promise<
   void
 > {
-  const files = await Deno.readdir("cli/tests/");
+  const files = [];
+  for await (const dirEntry of Deno.readdir("cli/tests/")) {
+    files.push(dirEntry);
+  }
   assertSameContent(files);
 });
 
@@ -77,7 +78,7 @@ unitTest({ perms: { read: false } }, async function readdirPerm(): Promise<
 > {
   let caughtError = false;
   try {
-    await Deno.readdir("tests/");
+    await Deno.readdir("tests/")[Symbol.asyncIterator]().next();
   } catch (e) {
     caughtError = true;
     assert(e instanceof Deno.errors.PermissionDenied);
diff --git a/cli/js/tests/remove_test.ts b/cli/js/tests/remove_test.ts
index 209558de7..b6f8aa320 100644
--- a/cli/js/tests/remove_test.ts
+++ b/cli/js/tests/remove_test.ts
@@ -10,7 +10,7 @@ unitTest(
     const path = Deno.makeTempDirSync() + "/subdir";
     Deno.mkdirSync(path);
     const pathInfo = Deno.statSync(path);
-    assert(pathInfo.isDirectory()); // check exist first
+    assert(pathInfo.isDirectory); // check exist first
     Deno.removeSync(path); // remove
     // We then check again after remove
     let err;
@@ -33,7 +33,7 @@ unitTest(
     const filename = Deno.makeTempDirSync() + "/test.txt";
     Deno.writeFileSync(filename, data, { mode: 0o666 });
     const fileInfo = Deno.statSync(filename);
-    assert(fileInfo.isFile()); // check exist first
+    assert(fileInfo.isFile); // check exist first
     Deno.removeSync(filename); // remove
     // We then check again after remove
     let err;
@@ -56,9 +56,9 @@ unitTest(
     Deno.mkdirSync(path, { recursive: true });
     Deno.mkdirSync(subPath);
     const pathInfo = Deno.statSync(path);
-    assert(pathInfo.isDirectory()); // check exist first
+    assert(pathInfo.isDirectory); // check exist first
     const subPathInfo = Deno.statSync(subPath);
-    assert(subPathInfo.isDirectory()); // check exist first
+    assert(subPathInfo.isDirectory); // check exist first
     let err;
     try {
       // Should not be able to recursively remove
@@ -94,7 +94,7 @@ unitTest(
       assertEquals(errOnWindows.message, "not implemented");
     } else {
       const pathInfo = Deno.lstatSync(danglingSymlinkPath);
-      assert(pathInfo.isSymlink());
+      assert(pathInfo.isSymlink);
       Deno.removeSync(danglingSymlinkPath);
       let err;
       try {
@@ -127,7 +127,7 @@ unitTest(
       assertEquals(errOnWindows.message, "not implemented");
     } else {
       const symlinkPathInfo = Deno.statSync(validSymlinkPath);
-      assert(symlinkPathInfo.isFile());
+      assert(symlinkPathInfo.isFile);
       Deno.removeSync(validSymlinkPath);
       let err;
       try {
@@ -159,7 +159,7 @@ unitTest(
     let path = Deno.makeTempDirSync() + "/dir/subdir";
     Deno.mkdirSync(path, { recursive: true });
     let pathInfo = Deno.statSync(path);
-    assert(pathInfo.isDirectory()); // check exist first
+    assert(pathInfo.isDirectory); // check exist first
     Deno.removeSync(path, { recursive: true }); // remove
     // We then check again after remove
     let err;
@@ -177,9 +177,9 @@ unitTest(
     Deno.mkdirSync(path, { recursive: true });
     Deno.mkdirSync(subPath);
     pathInfo = Deno.statSync(path);
-    assert(pathInfo.isDirectory()); // check exist first
+    assert(pathInfo.isDirectory); // check exist first
     const subPathInfo = Deno.statSync(subPath);
-    assert(subPathInfo.isDirectory()); // check exist first
+    assert(subPathInfo.isDirectory); // check exist first
     Deno.removeSync(path, { recursive: true }); // remove
     // We then check parent directory again after remove
     try {
@@ -201,7 +201,7 @@ unitTest(
     const filename = Deno.makeTempDirSync() + "/test.txt";
     Deno.writeFileSync(filename, data, { mode: 0o666 });
     const fileInfo = Deno.statSync(filename);
-    assert(fileInfo.isFile()); // check exist first
+    assert(fileInfo.isFile); // check exist first
     Deno.removeSync(filename, { recursive: true }); // remove
     // We then check again after remove
     let err;
@@ -247,7 +247,7 @@ unitTest(
     const path = Deno.makeTempDirSync() + "/dir/subdir";
     Deno.mkdirSync(path, { recursive: true });
     const pathInfo = Deno.statSync(path);
-    assert(pathInfo.isDirectory()); // check exist first
+    assert(pathInfo.isDirectory); // check exist first
     await Deno.remove(path); // remove
     // We then check again after remove
     let err;
@@ -270,7 +270,7 @@ unitTest(
     const filename = Deno.makeTempDirSync() + "/test.txt";
     Deno.writeFileSync(filename, data, { mode: 0o666 });
     const fileInfo = Deno.statSync(filename);
-    assert(fileInfo.isFile()); // check exist first
+    assert(fileInfo.isFile); // check exist first
     await Deno.remove(filename); // remove
     // We then check again after remove
     let err;
@@ -293,9 +293,9 @@ unitTest(
     Deno.mkdirSync(path, { recursive: true });
     Deno.mkdirSync(subPath);
     const pathInfo = Deno.statSync(path);
-    assert(pathInfo.isDirectory()); // check exist first
+    assert(pathInfo.isDirectory); // check exist first
     const subPathInfo = Deno.statSync(subPath);
-    assert(subPathInfo.isDirectory()); // check exist first
+    assert(subPathInfo.isDirectory); // check exist first
     let err;
     try {
       // Should not be able to recursively remove
@@ -330,7 +330,7 @@ unitTest(
       assertEquals(errOnWindows.message, "not implemented");
     } else {
       const pathInfo = Deno.lstatSync(danglingSymlinkPath);
-      assert(pathInfo.isSymlink());
+      assert(pathInfo.isSymlink);
       await Deno.remove(danglingSymlinkPath);
       let err;
       try {
@@ -363,7 +363,7 @@ unitTest(
       assertEquals(errOnWindows.message, "not implemented");
     } else {
       const symlinkPathInfo = Deno.statSync(validSymlinkPath);
-      assert(symlinkPathInfo.isFile());
+      assert(symlinkPathInfo.isFile);
       await Deno.remove(validSymlinkPath);
       let err;
       try {
@@ -397,7 +397,7 @@ unitTest(
     let path = Deno.makeTempDirSync() + "/dir/subdir";
     Deno.mkdirSync(path, { recursive: true });
     let pathInfo = Deno.statSync(path);
-    assert(pathInfo.isDirectory()); // check exist first
+    assert(pathInfo.isDirectory); // check exist first
     await Deno.remove(path, { recursive: true }); // remove
     // We then check again after remove
     let err;
@@ -415,9 +415,9 @@ unitTest(
     Deno.mkdirSync(path, { recursive: true });
     Deno.mkdirSync(subPath);
     pathInfo = Deno.statSync(path);
-    assert(pathInfo.isDirectory()); // check exist first
+    assert(pathInfo.isDirectory); // check exist first
     const subPathInfo = Deno.statSync(subPath);
-    assert(subPathInfo.isDirectory()); // check exist first
+    assert(subPathInfo.isDirectory); // check exist first
     await Deno.remove(path, { recursive: true }); // remove
     // We then check parent directory again after remove
     try {
@@ -439,7 +439,7 @@ unitTest(
     const filename = Deno.makeTempDirSync() + "/test.txt";
     Deno.writeFileSync(filename, data, { mode: 0o666 });
     const fileInfo = Deno.statSync(filename);
-    assert(fileInfo.isFile()); // check exist first
+    assert(fileInfo.isFile); // check exist first
     await Deno.remove(filename, { recursive: true }); // remove
     // We then check again after remove
     let err;
diff --git a/cli/js/tests/rename_test.ts b/cli/js/tests/rename_test.ts
index 45f6d709e..cbb3a55ce 100644
--- a/cli/js/tests/rename_test.ts
+++ b/cli/js/tests/rename_test.ts
@@ -16,12 +16,12 @@ function assertMissing(path: string): void {
 
 function assertFile(path: string): void {
   const info = Deno.lstatSync(path);
-  assert(info.isFile());
+  assert(info.isFile);
 }
 
 function assertDirectory(path: string, mode?: number): void {
   const info = Deno.lstatSync(path);
-  assert(info.isDirectory());
+  assert(info.isDirectory);
   if (Deno.build.os !== "win" && mode !== undefined) {
     assertEquals(info.mode! & 0o777, mode & ~Deno.umask());
   }
diff --git a/cli/js/tests/stat_test.ts b/cli/js/tests/stat_test.ts
index 78582900e..e4f4ae61e 100644
--- a/cli/js/tests/stat_test.ts
+++ b/cli/js/tests/stat_test.ts
@@ -5,16 +5,16 @@ import { unitTest, assert, assertEquals } from "./test_util.ts";
 // to create temp files.
 unitTest({ perms: { read: true } }, function statSyncSuccess(): void {
   const packageInfo = Deno.statSync("README.md");
-  assert(packageInfo.isFile());
-  assert(!packageInfo.isSymlink());
+  assert(packageInfo.isFile);
+  assert(!packageInfo.isSymlink);
 
   const modulesInfo = Deno.statSync("cli/tests/symlink_to_subdir");
-  assert(modulesInfo.isDirectory());
-  assert(!modulesInfo.isSymlink());
+  assert(modulesInfo.isDirectory);
+  assert(!modulesInfo.isSymlink);
 
   const testsInfo = Deno.statSync("cli/tests");
-  assert(testsInfo.isDirectory());
-  assert(!testsInfo.isSymlink());
+  assert(testsInfo.isDirectory);
+  assert(!testsInfo.isSymlink);
 });
 
 unitTest({ perms: { read: false } }, function statSyncPerm(): void {
@@ -45,16 +45,16 @@ unitTest({ perms: { read: true } }, function statSyncNotFound(): void {
 
 unitTest({ perms: { read: true } }, function lstatSyncSuccess(): void {
   const packageInfo = Deno.lstatSync("README.md");
-  assert(packageInfo.isFile());
-  assert(!packageInfo.isSymlink());
+  assert(packageInfo.isFile);
+  assert(!packageInfo.isSymlink);
 
   const modulesInfo = Deno.lstatSync("cli/tests/symlink_to_subdir");
-  assert(!modulesInfo.isDirectory());
-  assert(modulesInfo.isSymlink());
+  assert(!modulesInfo.isDirectory);
+  assert(modulesInfo.isSymlink);
 
   const coreInfo = Deno.lstatSync("core");
-  assert(coreInfo.isDirectory());
-  assert(!coreInfo.isSymlink());
+  assert(coreInfo.isDirectory);
+  assert(!coreInfo.isSymlink);
 });
 
 unitTest({ perms: { read: false } }, function lstatSyncPerm(): void {
@@ -87,16 +87,16 @@ unitTest({ perms: { read: true } }, async function statSuccess(): Promise<
   void
 > {
   const packageInfo = await Deno.stat("README.md");
-  assert(packageInfo.isFile());
-  assert(!packageInfo.isSymlink());
+  assert(packageInfo.isFile);
+  assert(!packageInfo.isSymlink);
 
   const modulesInfo = await Deno.stat("cli/tests/symlink_to_subdir");
-  assert(modulesInfo.isDirectory());
-  assert(!modulesInfo.isSymlink());
+  assert(modulesInfo.isDirectory);
+  assert(!modulesInfo.isSymlink);
 
   const testsInfo = await Deno.stat("cli/tests");
-  assert(testsInfo.isDirectory());
-  assert(!testsInfo.isSymlink());
+  assert(testsInfo.isDirectory);
+  assert(!testsInfo.isSymlink);
 });
 
 unitTest({ perms: { read: false } }, async function statPerm(): Promise<void> {
@@ -131,16 +131,16 @@ unitTest({ perms: { read: true } }, async function lstatSuccess(): Promise<
   void
 > {
   const packageInfo = await Deno.lstat("README.md");
-  assert(packageInfo.isFile());
-  assert(!packageInfo.isSymlink());
+  assert(packageInfo.isFile);
+  assert(!packageInfo.isSymlink);
 
   const modulesInfo = await Deno.lstat("cli/tests/symlink_to_subdir");
-  assert(!modulesInfo.isDirectory());
-  assert(modulesInfo.isSymlink());
+  assert(!modulesInfo.isDirectory);
+  assert(modulesInfo.isSymlink);
 
   const coreInfo = await Deno.lstat("core");
-  assert(coreInfo.isDirectory());
-  assert(!coreInfo.isSymlink());
+  assert(coreInfo.isDirectory);
+  assert(!coreInfo.isSymlink);
 });
 
 unitTest({ perms: { read: false } }, async function lstatPerm(): Promise<void> {
diff --git a/cli/js/tests/symlink_test.ts b/cli/js/tests/symlink_test.ts
index 25533fc64..0dde4fbad 100644
--- a/cli/js/tests/symlink_test.ts
+++ b/cli/js/tests/symlink_test.ts
@@ -21,8 +21,8 @@ unitTest(
     } else {
       const newNameInfoLStat = Deno.lstatSync(newname);
       const newNameInfoStat = Deno.statSync(newname);
-      assert(newNameInfoLStat.isSymlink());
-      assert(newNameInfoStat.isDirectory());
+      assert(newNameInfoLStat.isSymlink);
+      assert(newNameInfoStat.isDirectory);
     }
   }
 );
@@ -79,8 +79,8 @@ unitTest(
     } else {
       const newNameInfoLStat = Deno.lstatSync(newname);
       const newNameInfoStat = Deno.statSync(newname);
-      assert(newNameInfoLStat.isSymlink());
-      assert(newNameInfoStat.isDirectory());
+      assert(newNameInfoLStat.isSymlink);
+      assert(newNameInfoStat.isDirectory);
     }
   }
 );
diff --git a/cli/js/tests/test_util.ts b/cli/js/tests/test_util.ts
index a3b4b6ce4..fc0b8a390 100644
--- a/cli/js/tests/test_util.ts
+++ b/cli/js/tests/test_util.ts
@@ -327,7 +327,7 @@ unitTest(function permissionsMatches(): void {
 unitTest(
   { perms: { read: true } },
   function assertAllUnitTestFilesImported(): void {
-    const directoryTestFiles = Deno.readdirSync("./cli/js/tests/")
+    const directoryTestFiles = [...Deno.readdirSync("./cli/js/tests/")]
       .map((k) => k.name)
       .filter(
         (file) =>
diff --git a/cli/tests/016_double_await.ts b/cli/tests/016_double_await.ts
index 9b4801567..0f31b3a80 100644
--- a/cli/tests/016_double_await.ts
+++ b/cli/tests/016_double_await.ts
@@ -3,6 +3,6 @@
 (async (): Promise<void> => {
   const currDirInfo = await Deno.stat(".");
   const parentDirInfo = await Deno.stat("..");
-  console.log(currDirInfo.isDirectory());
-  console.log(parentDirInfo.isFile());
+  console.log(currDirInfo.isDirectory);
+  console.log(parentDirInfo.isFile);
 })();
diff --git a/std/fs/copy.ts b/std/fs/copy.ts
index b199e9167..05ce4b12c 100644
--- a/std/fs/copy.ts
+++ b/std/fs/copy.ts
@@ -35,7 +35,7 @@ async function ensureValidCopy(
     throw err;
   }
 
-  if (isCopyFolder && !destStat.isDirectory()) {
+  if (isCopyFolder && !destStat.isDirectory) {
     throw new Error(
       `Cannot overwrite non-directory '${dest}' with directory '${src}'.`
     );
@@ -63,7 +63,7 @@ function ensureValidCopySync(
     throw err;
   }
 
-  if (isCopyFolder && !destStat.isDirectory()) {
+  if (isCopyFolder && !destStat.isDirectory) {
     throw new Error(
       `Cannot overwrite non-directory '${dest}' with directory '${src}'.`
     );
@@ -157,17 +157,14 @@ async function copyDir(
     await Deno.utime(dest, srcStatInfo.accessed, srcStatInfo.modified);
   }
 
-  const files = await Deno.readdir(src);
-
-  for (const file of files) {
-    assert(file.name != null, "file.name must be set");
+  for await (const file of Deno.readdir(src)) {
     const srcPath = path.join(src, file.name);
     const destPath = path.join(dest, path.basename(srcPath as string));
-    if (file.isDirectory()) {
+    if (file.isDirectory) {
       await copyDir(srcPath, destPath, options);
-    } else if (file.isFile()) {
+    } else if (file.isFile) {
       await copyFile(srcPath, destPath, options);
-    } else if (file.isSymlink()) {
+    } else if (file.isSymlink) {
       await copySymLink(srcPath, destPath, options);
     }
   }
@@ -188,17 +185,15 @@ function copyDirSync(src: string, dest: string, options: CopyOptions): void {
     Deno.utimeSync(dest, srcStatInfo.accessed, srcStatInfo.modified);
   }
 
-  const files = Deno.readdirSync(src);
-
-  for (const file of files) {
+  for (const file of Deno.readdirSync(src)) {
     assert(file.name != null, "file.name must be set");
     const srcPath = path.join(src, file.name);
     const destPath = path.join(dest, path.basename(srcPath as string));
-    if (file.isDirectory()) {
+    if (file.isDirectory) {
       copyDirSync(srcPath, destPath, options);
-    } else if (file.isFile()) {
+    } else if (file.isFile) {
       copyFileSync(srcPath, destPath, options);
-    } else if (file.isSymlink()) {
+    } else if (file.isSymlink) {
       copySymlinkSync(srcPath, destPath, options);
     }
   }
@@ -228,17 +223,17 @@ export async function copy(
 
   const srcStat = await Deno.lstat(src);
 
-  if (srcStat.isDirectory() && isSubdir(src, dest)) {
+  if (srcStat.isDirectory && isSubdir(src, dest)) {
     throw new Error(
       `Cannot copy '${src}' to a subdirectory of itself, '${dest}'.`
     );
   }
 
-  if (srcStat.isDirectory()) {
+  if (srcStat.isDirectory) {
     await copyDir(src, dest, options);
-  } else if (srcStat.isFile()) {
+  } else if (srcStat.isFile) {
     await copyFile(src, dest, options);
-  } else if (srcStat.isSymlink()) {
+  } else if (srcStat.isSymlink) {
     await copySymLink(src, dest, options);
   }
 }
@@ -267,17 +262,17 @@ export function copySync(
 
   const srcStat = Deno.lstatSync(src);
 
-  if (srcStat.isDirectory() && isSubdir(src, dest)) {
+  if (srcStat.isDirectory && isSubdir(src, dest)) {
     throw new Error(
       `Cannot copy '${src}' to a subdirectory of itself, '${dest}'.`
     );
   }
 
-  if (srcStat.isDirectory()) {
+  if (srcStat.isDirectory) {
     copyDirSync(src, dest, options);
-  } else if (srcStat.isFile()) {
+  } else if (srcStat.isFile) {
     copyFileSync(src, dest, options);
-  } else if (srcStat.isSymlink()) {
+  } else if (srcStat.isSymlink) {
     copySymlinkSync(src, dest, options);
   }
 }
diff --git a/std/fs/copy_test.ts b/std/fs/copy_test.ts
index 0fbc90579..65e36a5fc 100644
--- a/std/fs/copy_test.ts
+++ b/std/fs/copy_test.ts
@@ -266,7 +266,7 @@ testCopy(
     }
 
     assert(
-      (await Deno.lstat(srcLink)).isSymlink(),
+      (await Deno.lstat(srcLink)).isSymlink,
       `'${srcLink}' should be symlink type`
     );
 
@@ -274,7 +274,7 @@ testCopy(
 
     const statInfo = await Deno.lstat(destLink);
 
-    assert(statInfo.isSymlink(), `'${destLink}' should be symlink type`);
+    assert(statInfo.isSymlink, `'${destLink}' should be symlink type`);
   }
 );
 
@@ -296,7 +296,7 @@ testCopy(
     await ensureSymlink(srcDir, srcLink);
 
     assert(
-      (await Deno.lstat(srcLink)).isSymlink(),
+      (await Deno.lstat(srcLink)).isSymlink,
       `'${srcLink}' should be symlink type`
     );
 
@@ -304,7 +304,7 @@ testCopy(
 
     const statInfo = await Deno.lstat(destLink);
 
-    assert(statInfo.isSymlink());
+    assert(statInfo.isSymlink);
   }
 );
 
@@ -506,7 +506,7 @@ testCopySync(
     }
 
     assert(
-      Deno.lstatSync(srcLink).isSymlink(),
+      Deno.lstatSync(srcLink).isSymlink,
       `'${srcLink}' should be symlink type`
     );
 
@@ -514,7 +514,7 @@ testCopySync(
 
     const statInfo = Deno.lstatSync(destLink);
 
-    assert(statInfo.isSymlink(), `'${destLink}' should be symlink type`);
+    assert(statInfo.isSymlink, `'${destLink}' should be symlink type`);
   }
 );
 
@@ -536,7 +536,7 @@ testCopySync(
     ensureSymlinkSync(originDir, srcLink);
 
     assert(
-      Deno.lstatSync(srcLink).isSymlink(),
+      Deno.lstatSync(srcLink).isSymlink,
       `'${srcLink}' should be symlink type`
     );
 
@@ -544,6 +544,6 @@ testCopySync(
 
     const statInfo = Deno.lstatSync(destLink);
 
-    assert(statInfo.isSymlink());
+    assert(statInfo.isSymlink);
   }
 );
diff --git a/std/fs/empty_dir.ts b/std/fs/empty_dir.ts
index 78b7a42f4..5e860c65f 100644
--- a/std/fs/empty_dir.ts
+++ b/std/fs/empty_dir.ts
@@ -10,7 +10,10 @@ const { readdir, readdirSync, mkdir, mkdirSync, remove, removeSync } = Deno;
  */
 export async function emptyDir(dir: string): Promise<void> {
   try {
-    const items = await readdir(dir);
+    const items = [];
+    for await (const dirEntry of readdir(dir)) {
+      items.push(dirEntry);
+    }
 
     while (items.length) {
       const item = items.shift();
@@ -38,7 +41,7 @@ export async function emptyDir(dir: string): Promise<void> {
  */
 export function emptyDirSync(dir: string): void {
   try {
-    const items = readdirSync(dir);
+    const items = [...readdirSync(dir)];
 
     // if directory already exist. then remove it's child item.
     while (items.length) {
diff --git a/std/fs/empty_dir_test.ts b/std/fs/empty_dir_test.ts
index f30f434df..59b12fbc9 100644
--- a/std/fs/empty_dir_test.ts
+++ b/std/fs/empty_dir_test.ts
@@ -20,7 +20,7 @@ Deno.test(async function emptyDirIfItNotExist(): Promise<void> {
   try {
     // check the dir
     const stat = await Deno.stat(testNestDir);
-    assertEquals(stat.isDirectory(), true);
+    assertEquals(stat.isDirectory, true);
   } finally {
     // remove the test dir
     await Deno.remove(testDir, { recursive: true });
@@ -36,7 +36,7 @@ Deno.test(function emptyDirSyncIfItNotExist(): void {
   try {
     // check the dir
     const stat = Deno.statSync(testNestDir);
-    assertEquals(stat.isDirectory(), true);
+    assertEquals(stat.isDirectory, true);
   } finally {
     // remove the test dir
     Deno.removeSync(testDir, { recursive: true });
@@ -54,10 +54,10 @@ Deno.test(async function emptyDirIfItExist(): Promise<void> {
 
   // before empty: make sure file/directory exist
   const beforeFileStat = await Deno.stat(testDirFile);
-  assertEquals(beforeFileStat.isFile(), true);
+  assertEquals(beforeFileStat.isFile, true);
 
   const beforeDirStat = await Deno.stat(testNestDir);
-  assertEquals(beforeDirStat.isDirectory(), true);
+  assertEquals(beforeDirStat.isDirectory, true);
 
   await emptyDir(testDir);
 
@@ -65,7 +65,7 @@ Deno.test(async function emptyDirIfItExist(): Promise<void> {
   try {
     // test dir still there
     const stat = await Deno.stat(testDir);
-    assertEquals(stat.isDirectory(), true);
+    assertEquals(stat.isDirectory, true);
 
     // nest directory have been remove
     await assertThrowsAsync(
@@ -97,10 +97,10 @@ Deno.test(function emptyDirSyncIfItExist(): void {
 
   // before empty: make sure file/directory exist
   const beforeFileStat = Deno.statSync(testDirFile);
-  assertEquals(beforeFileStat.isFile(), true);
+  assertEquals(beforeFileStat.isFile, true);
 
   const beforeDirStat = Deno.statSync(testNestDir);
-  assertEquals(beforeDirStat.isDirectory(), true);
+  assertEquals(beforeDirStat.isDirectory, true);
 
   emptyDirSync(testDir);
 
@@ -108,7 +108,7 @@ Deno.test(function emptyDirSyncIfItExist(): void {
   try {
     // test dir still there
     const stat = Deno.statSync(testDir);
-    assertEquals(stat.isDirectory(), true);
+    assertEquals(stat.isDirectory, true);
 
     // nest directory have been remove
     assertThrows((): void => {
diff --git a/std/fs/ensure_dir.ts b/std/fs/ensure_dir.ts
index a74261c61..ecc7356ef 100644
--- a/std/fs/ensure_dir.ts
+++ b/std/fs/ensure_dir.ts
@@ -10,7 +10,7 @@ const { lstat, lstatSync, mkdir, mkdirSync } = Deno;
 export async function ensureDir(dir: string): Promise<void> {
   try {
     const fileInfo = await lstat(dir);
-    if (!fileInfo.isDirectory()) {
+    if (!fileInfo.isDirectory) {
       throw new Error(
         `Ensure path exists, expected 'dir', got '${getFileInfoType(fileInfo)}'`
       );
@@ -33,7 +33,7 @@ export async function ensureDir(dir: string): Promise<void> {
 export function ensureDirSync(dir: string): void {
   try {
     const fileInfo = lstatSync(dir);
-    if (!fileInfo.isDirectory()) {
+    if (!fileInfo.isDirectory) {
       throw new Error(
         `Ensure path exists, expected 'dir', got '${getFileInfoType(fileInfo)}'`
       );
diff --git a/std/fs/ensure_file.ts b/std/fs/ensure_file.ts
index 77732164a..de6cab500 100644
--- a/std/fs/ensure_file.ts
+++ b/std/fs/ensure_file.ts
@@ -16,7 +16,7 @@ export async function ensureFile(filePath: string): Promise<void> {
   try {
     // if file exists
     const stat = await lstat(filePath);
-    if (!stat.isFile()) {
+    if (!stat.isFile) {
       throw new Error(
         `Ensure path exists, expected 'file', got '${getFileInfoType(stat)}'`
       );
@@ -47,7 +47,7 @@ export function ensureFileSync(filePath: string): void {
   try {
     // if file exists
     const stat = lstatSync(filePath);
-    if (!stat.isFile()) {
+    if (!stat.isFile) {
       throw new Error(
         `Ensure path exists, expected 'file', got '${getFileInfoType(stat)}'`
       );
diff --git a/std/fs/ensure_link_test.ts b/std/fs/ensure_link_test.ts
index 3c7720dc0..235650ebf 100644
--- a/std/fs/ensure_link_test.ts
+++ b/std/fs/ensure_link_test.ts
@@ -50,8 +50,8 @@ Deno.test(async function ensureLinkIfItExist(): Promise<void> {
   const srcStat = await Deno.lstat(testFile);
   const linkStat = await Deno.lstat(linkFile);
 
-  assertEquals(srcStat.isFile(), true);
-  assertEquals(linkStat.isFile(), true);
+  assertEquals(srcStat.isFile, true);
+  assertEquals(linkStat.isFile, true);
 
   // har link success. try to change one of them. they should be change both.
 
@@ -98,8 +98,8 @@ Deno.test(function ensureLinkSyncIfItExist(): void {
 
   const linkStat = Deno.lstatSync(linkFile);
 
-  assertEquals(srcStat.isFile(), true);
-  assertEquals(linkStat.isFile(), true);
+  assertEquals(srcStat.isFile, true);
+  assertEquals(linkStat.isFile, true);
 
   // har link success. try to change one of them. they should be change both.
 
diff --git a/std/fs/ensure_symlink_test.ts b/std/fs/ensure_symlink_test.ts
index 5188dc035..bbd31ef24 100644
--- a/std/fs/ensure_symlink_test.ts
+++ b/std/fs/ensure_symlink_test.ts
@@ -67,8 +67,8 @@ Deno.test(async function ensureSymlinkIfItExist(): Promise<void> {
   const srcStat = await Deno.lstat(testFile);
   const linkStat = await Deno.lstat(linkFile);
 
-  assertEquals(srcStat.isFile(), true);
-  assertEquals(linkStat.isSymlink(), true);
+  assertEquals(srcStat.isFile, true);
+  assertEquals(linkStat.isSymlink, true);
 
   await Deno.remove(testDir, { recursive: true });
 });
@@ -97,8 +97,8 @@ Deno.test(function ensureSymlinkSyncIfItExist(): void {
 
   const linkStat = Deno.lstatSync(linkFile);
 
-  assertEquals(srcStat.isFile(), true);
-  assertEquals(linkStat.isSymlink(), true);
+  assertEquals(srcStat.isFile, true);
+  assertEquals(linkStat.isSymlink, true);
 
   Deno.removeSync(testDir, { recursive: true });
 });
@@ -127,9 +127,9 @@ Deno.test(async function ensureSymlinkDirectoryIfItExist(): Promise<void> {
   const linkDirStat = await Deno.lstat(linkDir);
   const testFileStat = await Deno.lstat(testFile);
 
-  assertEquals(testFileStat.isFile(), true);
-  assertEquals(testDirStat.isDirectory(), true);
-  assertEquals(linkDirStat.isSymlink(), true);
+  assertEquals(testFileStat.isFile, true);
+  assertEquals(testDirStat.isDirectory, true);
+  assertEquals(linkDirStat.isSymlink, true);
 
   await Deno.remove(linkDir, { recursive: true });
   await Deno.remove(testDir, { recursive: true });
@@ -159,9 +159,9 @@ Deno.test(function ensureSymlinkSyncDirectoryIfItExist(): void {
   const linkDirStat = Deno.lstatSync(linkDir);
   const testFileStat = Deno.lstatSync(testFile);
 
-  assertEquals(testFileStat.isFile(), true);
-  assertEquals(testDirStat.isDirectory(), true);
-  assertEquals(linkDirStat.isSymlink(), true);
+  assertEquals(testFileStat.isFile, true);
+  assertEquals(testDirStat.isDirectory, true);
+  assertEquals(linkDirStat.isSymlink, true);
 
   Deno.removeSync(linkDir, { recursive: true });
   Deno.removeSync(testDir, { recursive: true });
diff --git a/std/fs/expand_glob.ts b/std/fs/expand_glob.ts
index 10a8c2c52..386f61ad5 100644
--- a/std/fs/expand_glob.ts
+++ b/std/fs/expand_glob.ts
@@ -8,7 +8,7 @@ import {
   joinGlobs,
   normalize,
 } from "../path/mod.ts";
-import { WalkInfo, walk, walkSync } from "./walk.ts";
+import { WalkEntry, walk, walkSync } from "./walk.ts";
 import { assert } from "../testing/asserts.ts";
 const { cwd, stat, statSync } = Deno;
 type FileInfo = Deno.FileInfo;
@@ -50,7 +50,7 @@ function throwUnlessNotFound(error: Error): void {
 
 /**
  * Expand the glob string from the specified `root` directory and yield each
- * result as a `WalkInfo` object.
+ * result as a `WalkEntry` object.
  */
 export async function* expandGlob(
   glob: string,
@@ -61,7 +61,7 @@ export async function* expandGlob(
     extended = false,
     globstar = false,
   }: ExpandGlobOptions = {}
-): AsyncIterableIterator<WalkInfo> {
+): AsyncIterableIterator<WalkEntry> {
   const globOptions: GlobOptions = { extended, globstar };
   const absRoot = isAbsolute(root)
     ? normalize(root)
@@ -84,7 +84,7 @@ export async function* expandGlob(
     fixedRoot = joinGlobs([fixedRoot, seg], globOptions);
   }
 
-  let fixedRootInfo: WalkInfo;
+  let fixedRootInfo: WalkEntry;
   try {
     fixedRootInfo = { filename: fixedRoot, info: await stat(fixedRoot) };
   } catch (error) {
@@ -92,10 +92,10 @@ export async function* expandGlob(
   }
 
   async function* advanceMatch(
-    walkInfo: WalkInfo,
+    walkInfo: WalkEntry,
     globSegment: string
-  ): AsyncIterableIterator<WalkInfo> {
-    if (!walkInfo.info.isDirectory()) {
+  ): AsyncIterableIterator<WalkEntry> {
+    if (!walkInfo.info.isDirectory) {
       return;
     } else if (globSegment == "..") {
       const parentPath = joinGlobs([walkInfo.filename, ".."], globOptions);
@@ -125,7 +125,7 @@ export async function* expandGlob(
     });
   }
 
-  let currentMatches: WalkInfo[] = [fixedRootInfo];
+  let currentMatches: WalkEntry[] = [fixedRootInfo];
   for (const segment of segments) {
     // Advancing the list of current matches may introduce duplicates, so we
     // pass everything through this Map.
@@ -136,20 +136,20 @@ export async function* expandGlob(
       }
     }
     currentMatches = [...nextMatchMap].sort().map(
-      ([filename, info]): WalkInfo => ({
+      ([filename, info]): WalkEntry => ({
         filename,
         info,
       })
     );
   }
   if (hasTrailingSep) {
-    currentMatches = currentMatches.filter(({ info }): boolean =>
-      info.isDirectory()
+    currentMatches = currentMatches.filter(
+      ({ info }): boolean => info.isDirectory
     );
   }
   if (!includeDirs) {
     currentMatches = currentMatches.filter(
-      ({ info }): boolean => !info.isDirectory()
+      ({ info }): boolean => !info.isDirectory
     );
   }
   yield* currentMatches;
@@ -165,7 +165,7 @@ export function* expandGlobSync(
     extended = false,
     globstar = false,
   }: ExpandGlobOptions = {}
-): IterableIterator<WalkInfo> {
+): IterableIterator<WalkEntry> {
   const globOptions: GlobOptions = { extended, globstar };
   const absRoot = isAbsolute(root)
     ? normalize(root)
@@ -188,7 +188,7 @@ export function* expandGlobSync(
     fixedRoot = joinGlobs([fixedRoot, seg], globOptions);
   }
 
-  let fixedRootInfo: WalkInfo;
+  let fixedRootInfo: WalkEntry;
   try {
     fixedRootInfo = { filename: fixedRoot, info: statSync(fixedRoot) };
   } catch (error) {
@@ -196,10 +196,10 @@ export function* expandGlobSync(
   }
 
   function* advanceMatch(
-    walkInfo: WalkInfo,
+    walkInfo: WalkEntry,
     globSegment: string
-  ): IterableIterator<WalkInfo> {
-    if (!walkInfo.info.isDirectory()) {
+  ): IterableIterator<WalkEntry> {
+    if (!walkInfo.info.isDirectory) {
       return;
     } else if (globSegment == "..") {
       const parentPath = joinGlobs([walkInfo.filename, ".."], globOptions);
@@ -229,7 +229,7 @@ export function* expandGlobSync(
     });
   }
 
-  let currentMatches: WalkInfo[] = [fixedRootInfo];
+  let currentMatches: WalkEntry[] = [fixedRootInfo];
   for (const segment of segments) {
     // Advancing the list of current matches may introduce duplicates, so we
     // pass everything through this Map.
@@ -240,20 +240,20 @@ export function* expandGlobSync(
       }
     }
     currentMatches = [...nextMatchMap].sort().map(
-      ([filename, info]): WalkInfo => ({
+      ([filename, info]): WalkEntry => ({
         filename,
         info,
       })
     );
   }
   if (hasTrailingSep) {
-    currentMatches = currentMatches.filter(({ info }): boolean =>
-      info.isDirectory()
+    currentMatches = currentMatches.filter(
+      ({ info }): boolean => info.isDirectory
     );
   }
   if (!includeDirs) {
     currentMatches = currentMatches.filter(
-      ({ info }): boolean => !info.isDirectory()
+      ({ info }): boolean => !info.isDirectory
     );
   }
   yield* currentMatches;
diff --git a/std/fs/move.ts b/std/fs/move.ts
index 48b1ef5f2..ee9498fd3 100644
--- a/std/fs/move.ts
+++ b/std/fs/move.ts
@@ -14,7 +14,7 @@ export async function move(
 ): Promise<void> {
   const srcStat = await Deno.stat(src);
 
-  if (srcStat.isDirectory() && isSubdir(src, dest)) {
+  if (srcStat.isDirectory && isSubdir(src, dest)) {
     throw new Error(
       `Cannot move '${src}' to a subdirectory of itself, '${dest}'.`
     );
@@ -41,7 +41,7 @@ export function moveSync(
 ): void {
   const srcStat = Deno.statSync(src);
 
-  if (srcStat.isDirectory() && isSubdir(src, dest)) {
+  if (srcStat.isDirectory && isSubdir(src, dest)) {
     throw new Error(
       `Cannot move '${src}' to a subdirectory of itself, '${dest}'.`
     );
diff --git a/std/fs/utils.ts b/std/fs/utils.ts
index ff11fbf13..48a98a0b1 100644
--- a/std/fs/utils.ts
+++ b/std/fs/utils.ts
@@ -35,11 +35,11 @@ export type PathType = "file" | "dir" | "symlink";
  *                 `lstat`
  */
 export function getFileInfoType(fileInfo: Deno.FileInfo): PathType | undefined {
-  return fileInfo.isFile()
+  return fileInfo.isFile
     ? "file"
-    : fileInfo.isDirectory()
+    : fileInfo.isDirectory
     ? "dir"
-    : fileInfo.isSymlink()
+    : fileInfo.isSymlink
     ? "symlink"
     : undefined;
 }
diff --git a/std/fs/walk.ts b/std/fs/walk.ts
index 3f178c0c5..e4cf4674f 100644
--- a/std/fs/walk.ts
+++ b/std/fs/walk.ts
@@ -4,7 +4,6 @@
 import { unimplemented, assert } from "../testing/asserts.ts";
 import { join } from "../path/mod.ts";
 const { readdir, readdirSync, stat, statSync } = Deno;
-type FileInfo = Deno.FileInfo;
 
 export interface WalkOptions {
   maxDepth?: number;
@@ -34,9 +33,9 @@ function include(
   return true;
 }
 
-export interface WalkInfo {
+export interface WalkEntry {
   filename: string;
-  info: FileInfo;
+  info: Deno.FileInfo;
 }
 
 /** Walks the file tree rooted at root, yielding each file or directory in the
@@ -55,7 +54,7 @@ export interface WalkInfo {
  *
  *      for await (const { filename, info } of walk(".")) {
  *        console.log(filename);
- *        assert(info.isFile());
+ *        assert(info.isFile);
  *      };
  */
 export async function* walk(
@@ -69,7 +68,7 @@ export async function* walk(
     match = undefined,
     skip = undefined,
   }: WalkOptions = {}
-): AsyncIterableIterator<WalkInfo> {
+): AsyncIterableIterator<WalkEntry> {
   if (maxDepth < 0) {
     return;
   }
@@ -79,9 +78,8 @@ export async function* walk(
   if (maxDepth < 1 || !include(root, undefined, undefined, skip)) {
     return;
   }
-  const ls: FileInfo[] = await readdir(root);
-  for (const info of ls) {
-    if (info.isSymlink()) {
+  for await (const dirEntry of readdir(root)) {
+    if (dirEntry.isSymlink) {
       if (followSymlinks) {
         // TODO(ry) Re-enable followSymlinks.
         unimplemented();
@@ -90,12 +88,11 @@ export async function* walk(
       }
     }
 
-    assert(info.name != null);
-    const filename = join(root, info.name);
+    const filename = join(root, dirEntry.name);
 
-    if (info.isFile()) {
+    if (dirEntry.isFile) {
       if (includeFiles && include(filename, exts, match, skip)) {
-        yield { filename, info };
+        yield { filename, info: dirEntry };
       }
     } else {
       yield* walk(filename, {
@@ -123,7 +120,7 @@ export function* walkSync(
     match = undefined,
     skip = undefined,
   }: WalkOptions = {}
-): IterableIterator<WalkInfo> {
+): IterableIterator<WalkEntry> {
   if (maxDepth < 0) {
     return;
   }
@@ -133,9 +130,8 @@ export function* walkSync(
   if (maxDepth < 1 || !include(root, undefined, undefined, skip)) {
     return;
   }
-  const ls: FileInfo[] = readdirSync(root);
-  for (const info of ls) {
-    if (info.isSymlink()) {
+  for (const dirEntry of readdirSync(root)) {
+    if (dirEntry.isSymlink) {
       if (followSymlinks) {
         unimplemented();
       } else {
@@ -143,12 +139,12 @@ export function* walkSync(
       }
     }
 
-    assert(info.name != null);
-    const filename = join(root, info.name);
+    assert(dirEntry.name != null);
+    const filename = join(root, dirEntry.name);
 
-    if (info.isFile()) {
+    if (dirEntry.isFile) {
       if (includeFiles && include(filename, exts, match, skip)) {
-        yield { filename, info };
+        yield { filename, info: dirEntry };
       }
     } else {
       yield* walkSync(filename, {
diff --git a/std/fs/walk_test.ts b/std/fs/walk_test.ts
index 453e2c5c4..6a44f5514 100644
--- a/std/fs/walk_test.ts
+++ b/std/fs/walk_test.ts
@@ -1,6 +1,6 @@
 const { cwd, chdir, makeTempDir, mkdir, open, symlink } = Deno;
 const { remove } = Deno;
-import { walk, walkSync, WalkOptions, WalkInfo } from "./walk.ts";
+import { walk, walkSync, WalkOptions, WalkEntry } from "./walk.ts";
 import { assert, assertEquals, assertThrowsAsync } from "../testing/asserts.ts";
 
 const isWindows = Deno.build.os == "win";
@@ -26,7 +26,7 @@ export function testWalk(
   Deno.test({ ignore, name: `[walk] ${name}`, fn });
 }
 
-function normalize({ filename }: WalkInfo): string {
+function normalize({ filename }: WalkEntry): string {
   return filename.replace(/\\/g, "/");
 }
 
diff --git a/std/http/file_server.ts b/std/http/file_server.ts
index 468e8a60e..90f8b8792 100755
--- a/std/http/file_server.ts
+++ b/std/http/file_server.ts
@@ -140,11 +140,10 @@ async function serveDir(
 ): Promise<Response> {
   const dirUrl = `/${posix.relative(target, dirPath)}`;
   const listEntry: EntryInfo[] = [];
-  const fileInfos = await readdir(dirPath);
-  for (const fileInfo of fileInfos) {
-    const filePath = posix.join(dirPath, fileInfo.name ?? "");
-    const fileUrl = posix.join(dirUrl, fileInfo.name ?? "");
-    if (fileInfo.name === "index.html" && fileInfo.isFile()) {
+  for await (const dirEntry of readdir(dirPath)) {
+    const filePath = posix.join(dirPath, dirEntry.name);
+    const fileUrl = posix.join(dirUrl, dirEntry.name);
+    if (dirEntry.name === "index.html" && dirEntry.isFile) {
       // in case index.html as dir...
       return serveFile(req, filePath);
     }
@@ -154,9 +153,9 @@ async function serveDir(
       mode = (await stat(filePath)).mode;
     } catch (e) {}
     listEntry.push({
-      mode: modeToString(fileInfo.isDirectory(), mode),
-      size: fileInfo.isFile() ? fileLenToString(fileInfo.size) : "",
-      name: fileInfo.name ?? "",
+      mode: modeToString(dirEntry.isDirectory, mode),
+      size: dirEntry.isFile ? fileLenToString(dirEntry.size) : "",
+      name: dirEntry.name,
       url: fileUrl,
     });
   }
@@ -333,7 +332,7 @@ function main(): void {
       let response: Response | undefined;
       try {
         const info = await stat(fsPath);
-        if (info.isDirectory()) {
+        if (info.isDirectory) {
           response = await serveDir(req, fsPath);
         } else {
           response = await serveFile(req, fsPath);
diff --git a/std/node/_fs/_fs_dir.ts b/std/node/_fs/_fs_dir.ts
index c5bb368c9..af27fb4f2 100644
--- a/std/node/_fs/_fs_dir.ts
+++ b/std/node/_fs/_fs_dir.ts
@@ -29,7 +29,10 @@ export default class Dir {
     return new Promise(async (resolve, reject) => {
       try {
         if (this.initializationOfDirectoryFilesIsRequired()) {
-          const denoFiles: Deno.FileInfo[] = await Deno.readdir(this.path);
+          const denoFiles: Deno.DirEntry[] = [];
+          for await (const dirEntry of Deno.readdir(this.path)) {
+            denoFiles.push(dirEntry);
+          }
           this.files = denoFiles.map((file) => new Dirent(file));
         }
         const nextFile = this.files.pop();
@@ -55,7 +58,7 @@ export default class Dir {
   readSync(): Dirent | null {
     if (this.initializationOfDirectoryFilesIsRequired()) {
       this.files.push(
-        ...Deno.readdirSync(this.path).map((file) => new Dirent(file))
+        ...[...Deno.readdirSync(this.path)].map((file) => new Dirent(file))
       );
     }
     const dirent: Dirent | undefined = this.files.pop();
diff --git a/std/node/_fs/_fs_dirent.ts b/std/node/_fs/_fs_dirent.ts
index 38cd23d88..55fbad142 100644
--- a/std/node/_fs/_fs_dirent.ts
+++ b/std/node/_fs/_fs_dirent.ts
@@ -1,7 +1,7 @@
 import { notImplemented } from "../_utils.ts";
 
 export default class Dirent {
-  constructor(private entry: Deno.FileInfo) {}
+  constructor(private entry: Deno.DirEntry) {}
 
   isBlockDevice(): boolean {
     return this.entry.blocks != null;
@@ -12,7 +12,7 @@ export default class Dirent {
   }
 
   isDirectory(): boolean {
-    return this.entry.isDirectory();
+    return this.entry.isDirectory;
   }
 
   isFIFO(): boolean {
@@ -23,7 +23,7 @@ export default class Dirent {
   }
 
   isFile(): boolean {
-    return this.entry.isFile();
+    return this.entry.isFile;
   }
 
   isSocket(): boolean {
@@ -32,7 +32,7 @@ export default class Dirent {
   }
 
   isSymbolicLink(): boolean {
-    return this.entry.isSymlink();
+    return this.entry.isSymlink;
   }
 
   get name(): string | null {
diff --git a/std/node/_fs/_fs_dirent_test.ts b/std/node/_fs/_fs_dirent_test.ts
index 1b1d38d38..548fa6b8a 100644
--- a/std/node/_fs/_fs_dirent_test.ts
+++ b/std/node/_fs/_fs_dirent_test.ts
@@ -2,7 +2,10 @@ const { test } = Deno;
 import { assert, assertEquals, assertThrows } from "../../testing/asserts.ts";
 import Dirent from "./_fs_dirent.ts";
 
-class FileInfoMock implements Deno.FileInfo {
+class DirEntryMock implements Deno.DirEntry {
+  isFile = false;
+  isDirectory = false;
+  isSymlink = false;
   size = -1;
   modified = -1;
   accessed = -1;
@@ -17,26 +20,12 @@ class FileInfoMock implements Deno.FileInfo {
   rdev = -1;
   blksize = -1;
   blocks: number | null = null;
-
-  isFileMock = false;
-  isDirectoryMock = false;
-  isSymlinkMock = false;
-
-  isFile(): boolean {
-    return this.isFileMock;
-  }
-  isDirectory(): boolean {
-    return this.isDirectoryMock;
-  }
-  isSymlink(): boolean {
-    return this.isSymlinkMock;
-  }
 }
 
 test({
   name: "Block devices are correctly identified",
   fn() {
-    const fileInfo: FileInfoMock = new FileInfoMock();
+    const fileInfo: DirEntryMock = new DirEntryMock();
     fileInfo.blocks = 5;
     assert(new Dirent(fileInfo).isBlockDevice());
     assert(!new Dirent(fileInfo).isCharacterDevice());
@@ -46,7 +35,7 @@ test({
 test({
   name: "Character devices are correctly identified",
   fn() {
-    const fileInfo: FileInfoMock = new FileInfoMock();
+    const fileInfo: DirEntryMock = new DirEntryMock();
     fileInfo.blocks = null;
     assert(new Dirent(fileInfo).isCharacterDevice());
     assert(!new Dirent(fileInfo).isBlockDevice());
@@ -56,10 +45,10 @@ test({
 test({
   name: "Directories are correctly identified",
   fn() {
-    const fileInfo: FileInfoMock = new FileInfoMock();
-    fileInfo.isDirectoryMock = true;
-    fileInfo.isFileMock = false;
-    fileInfo.isSymlinkMock = false;
+    const fileInfo: DirEntryMock = new DirEntryMock();
+    fileInfo.isDirectory = true;
+    fileInfo.isFile = false;
+    fileInfo.isSymlink = false;
     assert(new Dirent(fileInfo).isDirectory());
     assert(!new Dirent(fileInfo).isFile());
     assert(!new Dirent(fileInfo).isSymbolicLink());
@@ -69,10 +58,10 @@ test({
 test({
   name: "Files are correctly identified",
   fn() {
-    const fileInfo: FileInfoMock = new FileInfoMock();
-    fileInfo.isDirectoryMock = false;
-    fileInfo.isFileMock = true;
-    fileInfo.isSymlinkMock = false;
+    const fileInfo: DirEntryMock = new DirEntryMock();
+    fileInfo.isDirectory = false;
+    fileInfo.isFile = true;
+    fileInfo.isSymlink = false;
     assert(!new Dirent(fileInfo).isDirectory());
     assert(new Dirent(fileInfo).isFile());
     assert(!new Dirent(fileInfo).isSymbolicLink());
@@ -82,10 +71,10 @@ test({
 test({
   name: "Symlinks are correctly identified",
   fn() {
-    const fileInfo: FileInfoMock = new FileInfoMock();
-    fileInfo.isDirectoryMock = false;
-    fileInfo.isFileMock = false;
-    fileInfo.isSymlinkMock = true;
+    const fileInfo: DirEntryMock = new DirEntryMock();
+    fileInfo.isDirectory = false;
+    fileInfo.isFile = false;
+    fileInfo.isSymlink = true;
     assert(!new Dirent(fileInfo).isDirectory());
     assert(!new Dirent(fileInfo).isFile());
     assert(new Dirent(fileInfo).isSymbolicLink());
@@ -95,7 +84,7 @@ test({
 test({
   name: "File name is correct",
   fn() {
-    const fileInfo: FileInfoMock = new FileInfoMock();
+    const fileInfo: DirEntryMock = new DirEntryMock();
     fileInfo.name = "my_file";
     assertEquals(new Dirent(fileInfo).name, "my_file");
   },
@@ -104,7 +93,7 @@ test({
 test({
   name: "Socket and FIFO pipes aren't yet available",
   fn() {
-    const fileInfo: FileInfoMock = new FileInfoMock();
+    const fileInfo: DirEntryMock = new DirEntryMock();
     assertThrows(
       () => {
         new Dirent(fileInfo).isFIFO();
diff --git a/std/node/module.ts b/std/node/module.ts
index 522eaec7e..138cf916e 100644
--- a/std/node/module.ts
+++ b/std/node/module.ts
@@ -54,7 +54,7 @@ function stat(filename: string): StatResult {
   }
   try {
     const info = Deno.statSync(filename);
-    const result = info.isFile() ? 0 : 1;
+    const result = info.isFile ? 0 : 1;
     if (statCache !== null) statCache.set(filename, result);
     return result;
   } catch (e) {