feat(fs): add copy/copySync (denoland/deno_std#278)

Original: https://github.com/denoland/deno_std/commit/ab5b0887ccde0ad9f00f1943e27bd73bc483833b

9 files changed, 837 insertions, 0 deletions

diff --git a/fs/README.md b/fs/README.md
index 01780892d..8f4c472a8 100644
--- a/fs/README.md
+++ b/fs/README.md
@@ -129,6 +129,19 @@ moveSync("./foo", "./existingFolder", { overwrite: true });
 // Will overwrite existingFolder
 ```
 
+### copy
+
+copy a file or directory. Overwrites it if option provided
+
+```ts
+import { copy, copySync } from "https://deno.land/std/fs/mod.ts";
+
+copy("./foo", "./bar"); // returns a promise
+copySync("./foo", "./bar"); // void
+copySync("./foo", "./existingFolder", { overwrite: true });
+// Will overwrite existingFolder
+```
+
 ### readJson
 
 Reads a JSON file and then parses it into an object
diff --git a/fs/copy.ts b/fs/copy.ts
new file mode 100644
index 000000000..83c4e73ad
--- /dev/null
+++ b/fs/copy.ts
@@ -0,0 +1,260 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import * as path from "./path/mod.ts";
+import { ensureDir, ensureDirSync } from "./ensure_dir.ts";
+import { isSubdir, getFileInfoType } from "./utils.ts";
+
+export interface CopyOptions {
+  /**
+   * overwrite existing file or directory. Default is `false`
+   */
+  overwrite?: boolean;
+  /**
+   * When `true`, will set last modification and access times to the ones of the original source files.
+   * When `false`, timestamp behavior is OS-dependent.
+   * Default is `false`.
+   */
+  preserveTimestamps?: boolean;
+}
+
+async function ensureValidCopy(
+  src: string,
+  dest: string,
+  options: CopyOptions,
+  isCopyFolder: boolean = false
+): Promise<Deno.FileInfo> {
+  let destStat: Deno.FileInfo;
+
+  destStat = await Deno.lstat(dest).catch(
+    (): Promise<null> => Promise.resolve(null)
+  );
+
+  if (destStat) {
+    if (isCopyFolder && !destStat.isDirectory()) {
+      throw new Error(
+        `Cannot overwrite non-directory '${dest}' with directory '${src}'.`
+      );
+    }
+    if (!options.overwrite) {
+      throw new Error(`'${dest}' already exists.`);
+    }
+  }
+
+  return destStat;
+}
+
+function ensureValidCopySync(
+  src: string,
+  dest: string,
+  options: CopyOptions,
+  isCopyFolder: boolean = false
+): Deno.FileInfo {
+  let destStat: Deno.FileInfo;
+
+  try {
+    destStat = Deno.lstatSync(dest);
+  } catch {
+    // ignore error
+  }
+
+  if (destStat) {
+    if (isCopyFolder && !destStat.isDirectory()) {
+      throw new Error(
+        `Cannot overwrite non-directory '${dest}' with directory '${src}'.`
+      );
+    }
+    if (!options.overwrite) {
+      throw new Error(`'${dest}' already exists.`);
+    }
+  }
+
+  return destStat;
+}
+
+/* copy file to dest */
+async function copyFile(
+  src: string,
+  dest: string,
+  options: CopyOptions
+): Promise<void> {
+  await ensureValidCopy(src, dest, options);
+  await Deno.copyFile(src, dest);
+  if (options.preserveTimestamps) {
+    const statInfo = await Deno.stat(src);
+    await Deno.utime(dest, statInfo.accessed, statInfo.modified);
+  }
+}
+/* copy file to dest synchronously */
+function copyFileSync(src: string, dest: string, options: CopyOptions): void {
+  ensureValidCopySync(src, dest, options);
+  Deno.copyFileSync(src, dest);
+  if (options.preserveTimestamps) {
+    const statInfo = Deno.statSync(src);
+    Deno.utimeSync(dest, statInfo.accessed, statInfo.modified);
+  }
+}
+
+/* copy symlink to dest */
+async function copySymLink(
+  src: string,
+  dest: string,
+  options: CopyOptions
+): Promise<void> {
+  await ensureValidCopy(src, dest, options);
+  const originSrcFilePath = await Deno.readlink(src);
+  const type = getFileInfoType(await Deno.lstat(src));
+  await Deno.symlink(originSrcFilePath, dest, type);
+  if (options.preserveTimestamps) {
+    const statInfo = await Deno.lstat(src);
+    await Deno.utime(dest, statInfo.accessed, statInfo.modified);
+  }
+}
+
+/* copy symlink to dest synchronously */
+function copySymlinkSync(
+  src: string,
+  dest: string,
+  options: CopyOptions
+): void {
+  ensureValidCopySync(src, dest, options);
+  const originSrcFilePath = Deno.readlinkSync(src);
+  const type = getFileInfoType(Deno.lstatSync(src));
+  Deno.symlinkSync(originSrcFilePath, dest, type);
+  if (options.preserveTimestamps) {
+    const statInfo = Deno.lstatSync(src);
+    Deno.utimeSync(dest, statInfo.accessed, statInfo.modified);
+  }
+}
+
+/* copy folder from src to dest. */
+async function copyDir(
+  src: string,
+  dest: string,
+  options: CopyOptions
+): Promise<void> {
+  const destStat = await ensureValidCopy(src, dest, options, true);
+
+  if (!destStat) {
+    await ensureDir(dest);
+  }
+
+  if (options.preserveTimestamps) {
+    const srcStatInfo = await Deno.stat(src);
+    await Deno.utime(dest, srcStatInfo.accessed, srcStatInfo.modified);
+  }
+
+  const files = await Deno.readDir(src);
+
+  for (const file of files) {
+    const srcPath = file.path as string;
+    const destPath = path.join(dest, path.basename(srcPath as string));
+    if (file.isDirectory()) {
+      await copyDir(srcPath, destPath, options);
+    } else if (file.isFile()) {
+      await copyFile(srcPath, destPath, options);
+    } else if (file.isSymlink()) {
+      await copySymLink(srcPath, destPath, options);
+    }
+  }
+}
+
+/* copy folder from src to dest synchronously */
+function copyDirSync(src: string, dest: string, options: CopyOptions): void {
+  const destStat: Deno.FileInfo = ensureValidCopySync(src, dest, options, true);
+
+  if (!destStat) {
+    ensureDirSync(dest);
+  }
+
+  if (options.preserveTimestamps) {
+    const srcStatInfo = Deno.statSync(src);
+    Deno.utimeSync(dest, srcStatInfo.accessed, srcStatInfo.modified);
+  }
+
+  const files = Deno.readDirSync(src);
+
+  for (const file of files) {
+    const srcPath = file.path as string;
+    const destPath = path.join(dest, path.basename(srcPath as string));
+    if (file.isDirectory()) {
+      copyDirSync(srcPath, destPath, options);
+    } else if (file.isFile()) {
+      copyFileSync(srcPath, destPath, options);
+    } else if (file.isSymlink()) {
+      copySymlinkSync(srcPath, destPath, options);
+    }
+  }
+}
+
+/**
+ * Copy a file or directory. The directory can have contents. Like `cp -r`.
+ * @param src the file/directory path.
+ *            Note that if `src` is a directory it will copy everything inside of this directory,
+ *            not the entire directory itself
+ * @param dest the destination path. Note that if `src` is a file, `dest` cannot be a directory
+ * @param options
+ */
+export async function copy(
+  src: string,
+  dest: string,
+  options: CopyOptions = {}
+): Promise<void> {
+  src = path.resolve(src);
+  dest = path.resolve(dest);
+
+  if (src === dest) {
+    throw new Error("Source and destination cannot be the same.");
+  }
+
+  const srcStat = await Deno.lstat(src);
+
+  if (srcStat.isDirectory() && isSubdir(src, dest)) {
+    throw new Error(
+      `Cannot copy '${src}' to a subdirectory of itself, '${dest}'.`
+    );
+  }
+
+  if (srcStat.isDirectory()) {
+    await copyDir(src, dest, options);
+  } else if (srcStat.isFile()) {
+    await copyFile(src, dest, options);
+  } else if (srcStat.isSymlink()) {
+    await copySymLink(src, dest, options);
+  }
+}
+
+/**
+ * Copy a file or directory. The directory can have contents. Like `cp -r`.
+ * @param src the file/directory path.
+ *            Note that if `src` is a directory it will copy everything inside of this directory,
+ *            not the entire directory itself
+ * @param dest the destination path. Note that if `src` is a file, `dest` cannot be a directory
+ * @param options
+ */
+export function copySync(
+  src: string,
+  dest: string,
+  options: CopyOptions = {}
+): void {
+  src = path.resolve(src);
+  dest = path.resolve(dest);
+
+  if (src === dest) {
+    throw new Error("Source and destination cannot be the same.");
+  }
+
+  const srcStat = Deno.lstatSync(src);
+
+  if (srcStat.isDirectory() && isSubdir(src, dest)) {
+    throw new Error(
+      `Cannot copy '${src}' to a subdirectory of itself, '${dest}'.`
+    );
+  }
+
+  if (srcStat.isDirectory()) {
+    copyDirSync(src, dest, options);
+  } else if (srcStat.isFile()) {
+    copyFileSync(src, dest, options);
+  } else if (srcStat.isSymlink()) {
+    copySymlinkSync(src, dest, options);
+  }
+}
diff --git a/fs/copy_test.ts b/fs/copy_test.ts
new file mode 100644
index 000000000..03d439ec1
--- /dev/null
+++ b/fs/copy_test.ts
@@ -0,0 +1,558 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { test } from "../testing/mod.ts";
+import {
+  assertEquals,
+  assertThrows,
+  assertThrowsAsync,
+  assert
+} from "../testing/asserts.ts";
+import { copy, copySync } from "./copy.ts";
+import { exists, existsSync } from "./exists.ts";
+import * as path from "./path/mod.ts";
+import { ensureDir, ensureDirSync } from "./ensure_dir.ts";
+import { ensureFile, ensureFileSync } from "./ensure_file.ts";
+import { ensureSymlink, ensureSymlinkSync } from "./ensure_symlink.ts";
+
+const testdataDir = path.resolve("fs", "testdata");
+
+// TODO(axetroy): Add test for Windows once symlink is implemented for Windows.
+const isWindows = Deno.platform.os === "win";
+
+async function testCopy(
+  name: string,
+  cb: (tempDir: string) => Promise<void>
+): Promise<void> {
+  test({
+    name,
+    async fn(): Promise<void> {
+      const tempDir = await Deno.makeTempDir({
+        prefix: "deno_std_copy_async_test_"
+      });
+      await cb(tempDir);
+      await Deno.remove(tempDir, { recursive: true });
+    }
+  });
+}
+
+function testCopySync(name: string, cb: (tempDir: string) => void): void {
+  test({
+    name,
+    fn: (): void => {
+      const tempDir = Deno.makeTempDirSync({
+        prefix: "deno_std_copy_sync_test_"
+      });
+      cb(tempDir);
+      Deno.removeSync(tempDir, { recursive: true });
+    }
+  });
+}
+
+testCopy(
+  "[fs] copy file if it does no exist",
+  async (tempDir: string): Promise<void> => {
+    const srcFile = path.join(testdataDir, "copy_file_not_exists.txt");
+    const destFile = path.join(tempDir, "copy_file_not_exists_1.txt");
+    await assertThrowsAsync(
+      async (): Promise<void> => {
+        await copy(srcFile, destFile);
+      }
+    );
+  }
+);
+
+testCopy(
+  "[fs] copy if src and dest are the same paths",
+  async (tempDir: string): Promise<void> => {
+    const srcFile = path.join(tempDir, "copy_file_same.txt");
+    const destFile = path.join(tempDir, "copy_file_same.txt");
+    await assertThrowsAsync(
+      async (): Promise<void> => {
+        await copy(srcFile, destFile);
+      },
+      Error,
+      "Source and destination cannot be the same."
+    );
+  }
+);
+
+testCopy(
+  "[fs] copy file",
+  async (tempDir: string): Promise<void> => {
+    const srcFile = path.join(testdataDir, "copy_file.txt");
+    const destFile = path.join(tempDir, "copy_file_copy.txt");
+
+    const srcContent = new TextDecoder().decode(await Deno.readFile(srcFile));
+
+    assertEquals(
+      await exists(srcFile),
+      true,
+      `source should exist before copy`
+    );
+    assertEquals(
+      await exists(destFile),
+      false,
+      "destination should not exist before copy"
+    );
+
+    await copy(srcFile, destFile);
+
+    assertEquals(await exists(srcFile), true, "source should exist after copy");
+    assertEquals(
+      await exists(destFile),
+      true,
+      "destination should exist before copy"
+    );
+
+    const destContent = new TextDecoder().decode(await Deno.readFile(destFile));
+
+    assertEquals(
+      srcContent,
+      destContent,
+      "source and destination should have the same content"
+    );
+
+    // Copy again and it should throw an error.
+    await assertThrowsAsync(
+      async (): Promise<void> => {
+        await copy(srcFile, destFile);
+      },
+      Error,
+      `'${destFile}' already exists.`
+    );
+
+    // Modify destination file.
+    await Deno.writeFile(destFile, new TextEncoder().encode("txt copy"));
+
+    assertEquals(
+      new TextDecoder().decode(await Deno.readFile(destFile)),
+      "txt copy"
+    );
+
+    // Copy again with overwrite option.
+    await copy(srcFile, destFile, { overwrite: true });
+
+    // Make sure the file has been overwritten.
+    assertEquals(
+      new TextDecoder().decode(await Deno.readFile(destFile)),
+      "txt"
+    );
+  }
+);
+
+testCopy(
+  "[fs] copy with preserve timestamps",
+  async (tempDir: string): Promise<void> => {
+    const srcFile = path.join(testdataDir, "copy_file.txt");
+    const destFile = path.join(tempDir, "copy_file_copy.txt");
+
+    const srcStatInfo = await Deno.stat(srcFile);
+
+    assert(typeof srcStatInfo.accessed === "number");
+    assert(typeof srcStatInfo.modified === "number");
+
+    // Copy with overwrite and preserve timestamps options.
+    await copy(srcFile, destFile, {
+      overwrite: true,
+      preserveTimestamps: true
+    });
+
+    const destStatInfo = await Deno.stat(destFile);
+
+    assert(typeof destStatInfo.accessed === "number");
+    assert(typeof destStatInfo.modified === "number");
+    assertEquals(destStatInfo.accessed, srcStatInfo.accessed);
+    assertEquals(destStatInfo.modified, srcStatInfo.modified);
+  }
+);
+
+testCopy(
+  "[fs] copy directory to its subdirectory",
+  async (tempDir: string): Promise<void> => {
+    const srcDir = path.join(tempDir, "parent");
+    const destDir = path.join(srcDir, "child");
+
+    await ensureDir(srcDir);
+
+    await assertThrowsAsync(
+      async (): Promise<void> => {
+        await copy(srcDir, destDir);
+      },
+      Error,
+      `Cannot copy '${srcDir}' to a subdirectory of itself, '${destDir}'.`
+    );
+  }
+);
+
+testCopy(
+  "[fs] copy directory and destination exist and not a directory",
+  async (tempDir: string): Promise<void> => {
+    const srcDir = path.join(tempDir, "parent");
+    const destDir = path.join(tempDir, "child.txt");
+
+    await ensureDir(srcDir);
+    await ensureFile(destDir);
+
+    await assertThrowsAsync(
+      async (): Promise<void> => {
+        await copy(srcDir, destDir);
+      },
+      Error,
+      `Cannot overwrite non-directory '${destDir}' with directory '${srcDir}'.`
+    );
+  }
+);
+
+testCopy(
+  "[fs] copy directory",
+  async (tempDir: string): Promise<void> => {
+    const srcDir = path.join(testdataDir, "copy_dir");
+    const destDir = path.join(tempDir, "copy_dir");
+    const srcFile = path.join(srcDir, "0.txt");
+    const destFile = path.join(destDir, "0.txt");
+    const srcNestFile = path.join(srcDir, "nest", "0.txt");
+    const destNestFile = path.join(destDir, "nest", "0.txt");
+
+    await copy(srcDir, destDir);
+
+    assertEquals(await exists(destFile), true);
+    assertEquals(await exists(destNestFile), true);
+
+    // After copy. The source and destination should have the same content.
+    assertEquals(
+      new TextDecoder().decode(await Deno.readFile(srcFile)),
+      new TextDecoder().decode(await Deno.readFile(destFile))
+    );
+    assertEquals(
+      new TextDecoder().decode(await Deno.readFile(srcNestFile)),
+      new TextDecoder().decode(await Deno.readFile(destNestFile))
+    );
+
+    // Copy again without overwrite option and it should throw an error.
+    await assertThrowsAsync(
+      async (): Promise<void> => {
+        await copy(srcDir, destDir);
+      },
+      Error,
+      `'${destDir}' already exists.`
+    );
+
+    // Modify the file in the destination directory.
+    await Deno.writeFile(destNestFile, new TextEncoder().encode("nest copy"));
+    assertEquals(
+      new TextDecoder().decode(await Deno.readFile(destNestFile)),
+      "nest copy"
+    );
+
+    // Copy again with overwrite option.
+    await copy(srcDir, destDir, { overwrite: true });
+
+    // Make sure the file has been overwritten.
+    assertEquals(
+      new TextDecoder().decode(await Deno.readFile(destNestFile)),
+      "nest"
+    );
+  }
+);
+
+testCopy(
+  "[fs] copy symlink file",
+  async (tempDir: string): Promise<void> => {
+    const dir = path.join(testdataDir, "copy_dir_link_file");
+    const srcLink = path.join(dir, "0.txt");
+    const destLink = path.join(tempDir, "0_copy.txt");
+
+    if (isWindows) {
+      await assertThrowsAsync(
+        // (): Promise<void> => copy(srcLink, destLink),
+        (): Promise<void> => ensureSymlink(srcLink, destLink)
+      );
+      return;
+    }
+
+    assert(
+      (await Deno.lstat(srcLink)).isSymlink(),
+      `'${srcLink}' should be symlink type`
+    );
+
+    await copy(srcLink, destLink);
+
+    const statInfo = await Deno.lstat(destLink);
+
+    assert(statInfo.isSymlink(), `'${destLink}' should be symlink type`);
+  }
+);
+
+testCopy(
+  "[fs] copy symlink directory",
+  async (tempDir: string): Promise<void> => {
+    const srcDir = path.join(testdataDir, "copy_dir");
+    const srcLink = path.join(tempDir, "copy_dir_link");
+    const destLink = path.join(tempDir, "copy_dir_link_copy");
+
+    if (isWindows) {
+      await assertThrowsAsync(
+        // (): Promise<void> => copy(srcLink, destLink),
+        (): Promise<void> => ensureSymlink(srcLink, destLink)
+      );
+      return;
+    }
+
+    await ensureSymlink(srcDir, srcLink);
+
+    assert(
+      (await Deno.lstat(srcLink)).isSymlink(),
+      `'${srcLink}' should be symlink type`
+    );
+
+    await copy(srcLink, destLink);
+
+    const statInfo = await Deno.lstat(destLink);
+
+    assert(statInfo.isSymlink());
+  }
+);
+
+testCopySync(
+  "[fs] copy file synchronously if it does not exist",
+  (tempDir: string): void => {
+    const srcFile = path.join(testdataDir, "copy_file_not_exists_sync.txt");
+    const destFile = path.join(tempDir, "copy_file_not_exists_1_sync.txt");
+    assertThrows(
+      (): void => {
+        copySync(srcFile, destFile);
+      }
+    );
+  }
+);
+
+testCopySync(
+  "[fs] copy synchronously with preserve timestamps",
+  (tempDir: string): void => {
+    const srcFile = path.join(testdataDir, "copy_file.txt");
+    const destFile = path.join(tempDir, "copy_file_copy.txt");
+
+    const srcStatInfo = Deno.statSync(srcFile);
+
+    assert(typeof srcStatInfo.accessed === "number");
+    assert(typeof srcStatInfo.modified === "number");
+
+    // Copy with overwrite and preserve timestamps options.
+    copySync(srcFile, destFile, {
+      overwrite: true,
+      preserveTimestamps: true
+    });
+
+    const destStatInfo = Deno.statSync(destFile);
+
+    assert(typeof destStatInfo.accessed === "number");
+    assert(typeof destStatInfo.modified === "number");
+    assertEquals(destStatInfo.accessed, srcStatInfo.accessed);
+    assertEquals(destStatInfo.modified, srcStatInfo.modified);
+  }
+);
+
+testCopySync(
+  "[fs] copy synchronously if src and dest are the same paths",
+  (): void => {
+    const srcFile = path.join(testdataDir, "copy_file_same_sync.txt");
+    assertThrows(
+      (): void => {
+        copySync(srcFile, srcFile);
+      },
+      Error,
+      "Source and destination cannot be the same."
+    );
+  }
+);
+
+testCopySync(
+  "[fs] copy file synchronously",
+  (tempDir: string): void => {
+    const srcFile = path.join(testdataDir, "copy_file.txt");
+    const destFile = path.join(tempDir, "copy_file_copy_sync.txt");
+
+    const srcContent = new TextDecoder().decode(Deno.readFileSync(srcFile));
+
+    assertEquals(existsSync(srcFile), true);
+    assertEquals(existsSync(destFile), false);
+
+    copySync(srcFile, destFile);
+
+    assertEquals(existsSync(srcFile), true);
+    assertEquals(existsSync(destFile), true);
+
+    const destContent = new TextDecoder().decode(Deno.readFileSync(destFile));
+
+    assertEquals(srcContent, destContent);
+
+    // Copy again without overwrite option and it should throw an error.
+    assertThrows(
+      (): void => {
+        copySync(srcFile, destFile);
+      },
+      Error,
+      `'${destFile}' already exists.`
+    );
+
+    // Modify destination file.
+    Deno.writeFileSync(destFile, new TextEncoder().encode("txt copy"));
+
+    assertEquals(
+      new TextDecoder().decode(Deno.readFileSync(destFile)),
+      "txt copy"
+    );
+
+    // Copy again with overwrite option.
+    copySync(srcFile, destFile, { overwrite: true });
+
+    // Make sure the file has been overwritten.
+    assertEquals(new TextDecoder().decode(Deno.readFileSync(destFile)), "txt");
+  }
+);
+
+testCopySync(
+  "[fs] copy directory synchronously to its subdirectory",
+  (tempDir: string): void => {
+    const srcDir = path.join(tempDir, "parent");
+    const destDir = path.join(srcDir, "child");
+
+    ensureDirSync(srcDir);
+
+    assertThrows(
+      (): void => {
+        copySync(srcDir, destDir);
+      },
+      Error,
+      `Cannot copy '${srcDir}' to a subdirectory of itself, '${destDir}'.`
+    );
+  }
+);
+
+testCopySync(
+  "[fs] copy directory synchronously, and destination exist and not a directory",
+  (tempDir: string): void => {
+    const srcDir = path.join(tempDir, "parent_sync");
+    const destDir = path.join(tempDir, "child.txt");
+
+    ensureDirSync(srcDir);
+    ensureFileSync(destDir);
+
+    assertThrows(
+      (): void => {
+        copySync(srcDir, destDir);
+      },
+      Error,
+      `Cannot overwrite non-directory '${destDir}' with directory '${srcDir}'.`
+    );
+  }
+);
+
+testCopySync(
+  "[fs] copy directory synchronously",
+  (tempDir: string): void => {
+    const srcDir = path.join(testdataDir, "copy_dir");
+    const destDir = path.join(tempDir, "copy_dir_copy_sync");
+    const srcFile = path.join(srcDir, "0.txt");
+    const destFile = path.join(destDir, "0.txt");
+    const srcNestFile = path.join(srcDir, "nest", "0.txt");
+    const destNestFile = path.join(destDir, "nest", "0.txt");
+
+    copySync(srcDir, destDir);
+
+    assertEquals(existsSync(destFile), true);
+    assertEquals(existsSync(destNestFile), true);
+
+    // After copy. The source and destination should have the same content.
+    assertEquals(
+      new TextDecoder().decode(Deno.readFileSync(srcFile)),
+      new TextDecoder().decode(Deno.readFileSync(destFile))
+    );
+    assertEquals(
+      new TextDecoder().decode(Deno.readFileSync(srcNestFile)),
+      new TextDecoder().decode(Deno.readFileSync(destNestFile))
+    );
+
+    // Copy again without overwrite option and it should throw an error.
+    assertThrows(
+      (): void => {
+        copySync(srcDir, destDir);
+      },
+      Error,
+      `'${destDir}' already exists.`
+    );
+
+    // Modify the file in the destination directory.
+    Deno.writeFileSync(destNestFile, new TextEncoder().encode("nest copy"));
+    assertEquals(
+      new TextDecoder().decode(Deno.readFileSync(destNestFile)),
+      "nest copy"
+    );
+
+    // Copy again with overwrite option.
+    copySync(srcDir, destDir, { overwrite: true });
+
+    // Make sure the file has been overwritten.
+    assertEquals(
+      new TextDecoder().decode(Deno.readFileSync(destNestFile)),
+      "nest"
+    );
+  }
+);
+
+testCopySync(
+  "[fs] copy symlink file synchronously",
+  (tempDir: string): void => {
+    const dir = path.join(testdataDir, "copy_dir_link_file");
+    const srcLink = path.join(dir, "0.txt");
+    const destLink = path.join(tempDir, "0_copy.txt");
+
+    if (isWindows) {
+      assertThrows(
+        // (): void => copySync(srcLink, destLink),
+        (): void => ensureSymlinkSync(srcLink, destLink)
+      );
+      return;
+    }
+
+    assert(
+      Deno.lstatSync(srcLink).isSymlink(),
+      `'${srcLink}' should be symlink type`
+    );
+
+    copySync(srcLink, destLink);
+
+    const statInfo = Deno.lstatSync(destLink);
+
+    assert(statInfo.isSymlink(), `'${destLink}' should be symlink type`);
+  }
+);
+
+testCopySync(
+  "[fs] copy symlink directory synchronously",
+  (tempDir: string): void => {
+    const originDir = path.join(testdataDir, "copy_dir");
+    const srcLink = path.join(tempDir, "copy_dir_link");
+    const destLink = path.join(tempDir, "copy_dir_link_copy");
+
+    if (isWindows) {
+      assertThrows(
+        // (): void => copySync(srcLink, destLink),
+        (): void => ensureSymlinkSync(srcLink, destLink)
+      );
+      return;
+    }
+
+    ensureSymlinkSync(originDir, srcLink);
+
+    assert(
+      Deno.lstatSync(srcLink).isSymlink(),
+      `'${srcLink}' should be symlink type`
+    );
+
+    copySync(srcLink, destLink);
+
+    const statInfo = Deno.lstatSync(destLink);
+
+    assert(statInfo.isSymlink());
+  }
+);
diff --git a/fs/mod.ts b/fs/mod.ts
index 8635911a4..edbd7009f 100644
--- a/fs/mod.ts
+++ b/fs/mod.ts
@@ -8,6 +8,7 @@ export * from "./exists.ts";
 export * from "./glob.ts";
 export * from "./globrex.ts";
 export * from "./move.ts";
+export * from "./copy.ts";
 export * from "./read_file_str.ts";
 export * from "./write_file_str.ts";
 export * from "./read_json.ts";
diff --git a/fs/test.ts b/fs/test.ts
index 90e3c4688..43d6550b8 100644
--- a/fs/test.ts
+++ b/fs/test.ts
@@ -11,6 +11,7 @@ import "./ensure_file_test.ts";
 import "./ensure_symlink_test.ts";
 import "./ensure_link_test.ts";
 import "./move_test.ts";
+import "./copy_test.ts";
 import "./read_json_test.ts";
 import "./write_json_test.ts";
 import "./read_file_str_test.ts";
diff --git a/fs/testdata/copy_dir/0.txt b/fs/testdata/copy_dir/0.txt
new file mode 100644
index 000000000..f3a34851d
--- /dev/null
+++ b/fs/testdata/copy_dir/0.txt
@@ -0,0 +1 @@
+text
\ No newline at end of file
diff --git a/fs/testdata/copy_dir/nest/0.txt b/fs/testdata/copy_dir/nest/0.txt
new file mode 100644
index 000000000..cd1b98cb3
--- /dev/null
+++ b/fs/testdata/copy_dir/nest/0.txt
@@ -0,0 +1 @@
+nest
\ No newline at end of file
diff --git a/fs/testdata/copy_dir_link_file/0.txt b/fs/testdata/copy_dir_link_file/0.txt
new file mode 120000
index 000000000..63413ea1c
--- /dev/null
+++ b/fs/testdata/copy_dir_link_file/0.txt
@@ -0,0 +1 @@
+./fs/testdata/copy_dir/0.txt
\ No newline at end of file
diff --git a/fs/testdata/copy_file.txt b/fs/testdata/copy_file.txt
new file mode 100644
index 000000000..84c22fd8a
--- /dev/null
+++ b/fs/testdata/copy_file.txt
@@ -0,0 +1 @@
+txt
\ No newline at end of file