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

14 files changed, 165 insertions, 198 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) =>