3 files changed, 31 insertions, 1 deletions
diff --git a/cli/js/deno_unstable.ts b/cli/js/deno_unstable.ts
index 2327b554d..e7a0510be 100644
--- a/cli/js/deno_unstable.ts
+++ b/cli/js/deno_unstable.ts
@@ -5,7 +5,7 @@
 export { umask } from "./ops/fs/umask.ts";
 export { linkSync, link } from "./ops/fs/link.ts";
 export { fstatSync, fstat } from "./ops/fs/stat.ts";
-export { fsyncSync, fsync } from "./ops/fs/sync.ts";
+export { fdatasyncSync, fdatasync, fsyncSync, fsync } from "./ops/fs/sync.ts";
 export { symlinkSync, symlink } from "./ops/fs/symlink.ts";
 export { loadavg, osRelease, hostname } from "./ops/os.ts";
 export { openPlugin } from "./ops/plugins.ts";
diff --git a/cli/js/lib.deno.unstable.d.ts b/cli/js/lib.deno.unstable.d.ts
index cc7dea987..f4a7b2786 100644
--- a/cli/js/lib.deno.unstable.d.ts
+++ b/cli/js/lib.deno.unstable.d.ts
@@ -1119,6 +1119,28 @@ declare namespace Deno {
    */
   export function ftruncate(rid: number, len?: number): Promise<void>;
 
+  /* **UNSTABLE**: New API, yet to be vetted.
+   * Synchronously flushes any pending data operations of the given file stream to disk.
+   *  ```ts
+   * const file = Deno.openSync("my_file.txt", { read: true, write: true, create: true });
+   * Deno.writeSync(file.rid, new TextEncoder().encode("Hello World"));
+   * Deno.fdatasyncSync(file.rid);
+   * console.log(new TextDecoder().decode(Deno.readFileSync("my_file.txt"))); // Hello World
+   * ```
+   */
+  export function fdatasyncSync(rid: number): void;
+
+  /** **UNSTABLE**: New API, yet to be vetted.
+   * Flushes any pending data operations of the given file stream to disk.
+   *  ```ts
+   * const file = await Deno.open("my_file.txt", { read: true, write: true, create: true });
+   * await Deno.write(file.rid, new TextEncoder().encode("Hello World"));
+   * await Deno.fdatasync(file.rid);
+   * console.log(new TextDecoder().decode(await Deno.readFile("my_file.txt"))); // Hello World
+   * ```
+   */
+  export function fdatasync(rid: number): Promise<void>;
+
   /** **UNSTABLE**: New API, yet to be vetted.
    * Synchronously flushes any pending data and metadata operations of the given file stream to disk.
    *  ```ts
diff --git a/cli/js/ops/fs/sync.ts b/cli/js/ops/fs/sync.ts
index 5d5de7242..567aab55b 100644
--- a/cli/js/ops/fs/sync.ts
+++ b/cli/js/ops/fs/sync.ts
@@ -1,6 +1,14 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 import { sendSync, sendAsync } from "../dispatch_json.ts";
 
+export function fdatasyncSync(rid: number): void {
+  sendSync("op_fdatasync", { rid });
+}
+
+export async function fdatasync(rid: number): Promise<void> {
+  await sendAsync("op_fdatasync", { rid });
+}
+
 export function fsyncSync(rid: number): void {
   sendSync("op_fsync", { rid });
 }