3 files changed, 124 insertions, 3 deletions

diff --git a/std/node/_fs/_fs_writeFile.ts b/std/node/_fs/_fs_writeFile.ts
index c9f7fe125..b46620d9b 100644
--- a/std/node/_fs/_fs_writeFile.ts
+++ b/std/node/_fs/_fs_writeFile.ts
@@ -63,3 +63,47 @@ export function writeFile(
     }
   })();
 }
+
+export function writeFileSync(
+  pathOrRid: string | number,
+  data: string | Uint8Array,
+  options?: string | WriteFileOptions
+): void {
+  const flag: string | undefined = isFileOptions(options)
+    ? options.flag
+    : undefined;
+
+  const mode: number | undefined = isFileOptions(options)
+    ? options.mode
+    : undefined;
+
+  const encoding = getEncoding(options) || "utf8";
+  const openOptions = getOpenOptions(flag || "w");
+
+  if (typeof data === "string" && encoding === "utf8")
+    data = new TextEncoder().encode(data) as Uint8Array;
+
+  const isRid = typeof pathOrRid === "number";
+  let file;
+
+  let error: Error | null = null;
+  try {
+    file = isRid
+      ? new Deno.File(pathOrRid as number)
+      : Deno.openSync(pathOrRid as string, openOptions);
+
+    if (!isRid && mode) {
+      if (Deno.build.os === "windows") notImplemented(`"mode" on Windows`);
+      Deno.chmodSync(pathOrRid as string, mode);
+    }
+
+    Deno.writeAllSync(file, data as Uint8Array);
+  } catch (e) {
+    error = e;
+  } finally {
+    // Make sure to close resource
+    if (!isRid && file) file.close();
+
+    if (error) throw error;
+  }
+}
diff --git a/std/node/_fs/_fs_writeFile_test.ts b/std/node/_fs/_fs_writeFile_test.ts
index 427062034..f3598f0b0 100644
--- a/std/node/_fs/_fs_writeFile_test.ts
+++ b/std/node/_fs/_fs_writeFile_test.ts
@@ -7,11 +7,11 @@ import {
   assertNotEquals,
   assertThrows,
 } from "../../testing/asserts.ts";
-import { writeFile } from "./_fs_writeFile.ts";
+import { writeFile, writeFileSync } from "./_fs_writeFile.ts";
 
 const decoder = new TextDecoder("utf-8");
 
-test("Invalid encoding results in error()", function fn() {
+test("Callback must be a function error", function fn() {
   assertThrows(
     () => {
       writeFile("some/path", "some data", "utf8");
@@ -29,6 +29,15 @@ test("Invalid encoding results in error()", function testEncodingErrors() {
     Error,
     `The value "made-up-encoding" is invalid for option "encoding"`
   );
+
+  assertThrows(
+    () => {
+      writeFileSync("some/path", "some data", "made-up-encoding");
+    },
+    Error,
+    `The value "made-up-encoding" is invalid for option "encoding"`
+  );
+
   assertThrows(
     () => {
       writeFile(
@@ -43,6 +52,16 @@ test("Invalid encoding results in error()", function testEncodingErrors() {
     Error,
     `The value "made-up-encoding" is invalid for option "encoding"`
   );
+
+  assertThrows(
+    () => {
+      writeFileSync("some/path", "some data", {
+        encoding: "made-up-encoding",
+      });
+    },
+    Error,
+    `The value "made-up-encoding" is invalid for option "encoding"`
+  );
 });
 
 test("Unsupported encoding results in error()", function testUnsupportedEncoding() {
@@ -53,6 +72,15 @@ test("Unsupported encoding results in error()", function testUnsupportedEncoding
     Error,
     `Not implemented: "hex" encoding`
   );
+
+  assertThrows(
+    () => {
+      writeFileSync("some/path", "some data", "hex");
+    },
+    Error,
+    `Not implemented: "hex" encoding`
+  );
+
   assertThrows(
     () => {
       writeFile(
@@ -67,6 +95,16 @@ test("Unsupported encoding results in error()", function testUnsupportedEncoding
     Error,
     `Not implemented: "base64" encoding`
   );
+
+  assertThrows(
+    () => {
+      writeFileSync("some/path", "some data", {
+        encoding: "base64",
+      });
+    },
+    Error,
+    `Not implemented: "base64" encoding`
+  );
 });
 
 test("Data is written to correct rid", async function testCorrectWriteUsingRid() {
@@ -160,3 +198,41 @@ test("Mode is not set when rid is passed", async function testCorrectFileModeRid
   assert(fileInfo.mode);
   assertNotEquals(fileInfo.mode & 0o777, 0o777);
 });
+
+test("Data is written synchronously to correct rid", function testCorrectWriteSyncUsingRid() {
+  const tempFile: string = Deno.makeTempFileSync();
+  const file: Deno.File = Deno.openSync(tempFile, {
+    create: true,
+    write: true,
+    read: true,
+  });
+
+  writeFileSync(file.rid, "hello world");
+  Deno.close(file.rid);
+
+  const data = Deno.readFileSync(tempFile);
+  Deno.removeSync(tempFile);
+  assertEquals(decoder.decode(data), "hello world");
+});
+
+test("Data is written synchronously to correct file", function testCorrectWriteSyncUsingPath() {
+  const file = "_fs_writeFileSync_test_file";
+
+  writeFileSync(file, "hello world");
+
+  const data = Deno.readFileSync(file);
+  Deno.removeSync(file);
+  assertEquals(decoder.decode(data), "hello world");
+});
+
+test("Mode is correctly set when writing synchronously", function testCorrectFileModeSync() {
+  if (Deno.build.os === "windows") return;
+  const filename = "_fs_writeFileSync_test_file.txt";
+
+  writeFileSync(filename, "hello world", { mode: 0o777 });
+
+  const fileInfo = Deno.statSync(filename);
+  Deno.removeSync(filename);
+  assert(fileInfo && fileInfo.mode);
+  assertEquals(fileInfo.mode & 0o777, 0o777);
+});
diff --git a/std/node/fs.ts b/std/node/fs.ts
index 737f2a0e9..4bb514c7a 100644
--- a/std/node/fs.ts
+++ b/std/node/fs.ts
@@ -11,7 +11,7 @@ import { readlink, readlinkSync } from "./_fs/_fs_readlink.ts";
 import { exists, existsSync } from "./_fs/_fs_exists.ts";
 import { mkdir, mkdirSync } from "./_fs/_fs_mkdir.ts";
 import { copyFile, copyFileSync } from "./_fs/_fs_copy.ts";
-import { writeFile } from "./_fs/_fs_writeFile.ts";
+import { writeFile, writeFileSync } from "./_fs/_fs_writeFile.ts";
 import * as promises from "./_fs/promises/mod.ts";
 
 export {
@@ -37,5 +37,6 @@ export {
   mkdir,
   mkdirSync,
   writeFile,
+  writeFileSync,
   promises,
 };