feat(std/node): fs.writefile / fs.promises.writeFile (#5054)

3 files changed, 137 insertions, 0 deletions

diff --git a/std/node/_fs/promises/_fs_writeFile.ts b/std/node/_fs/promises/_fs_writeFile.ts
new file mode 100644
index 000000000..a8f9586a2
--- /dev/null
+++ b/std/node/_fs/promises/_fs_writeFile.ts
@@ -0,0 +1,17 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+import { WriteFileOptions } from "../_fs_common.ts";
+
+import { writeFile as writeFileCallback } from "../_fs_writeFile.ts";
+
+export function writeFile(
+  pathOrRid: string | number,
+  data: string | Uint8Array,
+  options?: string | WriteFileOptions
+): Promise<void> {
+  return new Promise((resolve, reject) => {
+    writeFileCallback(pathOrRid, data, options, (err?: Error | null) => {
+      if (err) return reject(err);
+      resolve();
+    });
+  });
+}
diff --git a/std/node/_fs/promises/_fs_writeFile_test.ts b/std/node/_fs/promises/_fs_writeFile_test.ts
new file mode 100644
index 000000000..c67a7947a
--- /dev/null
+++ b/std/node/_fs/promises/_fs_writeFile_test.ts
@@ -0,0 +1,119 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+const { test } = Deno;
+
+import {
+  assert,
+  assertEquals,
+  assertNotEquals,
+  assertThrowsAsync,
+} from "../../../testing/asserts.ts";
+import { writeFile } from "./_fs_writeFile.ts";
+
+const decoder = new TextDecoder("utf-8");
+
+test("Invalid encoding results in error()", function testEncodingErrors() {
+  assertThrowsAsync(
+    async () => {
+      await writeFile("some/path", "some data", "made-up-encoding");
+    },
+    Error,
+    `The value "made-up-encoding" is invalid for option "encoding"`
+  );
+  assertThrowsAsync(
+    async () => {
+      await writeFile("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() {
+  assertThrowsAsync(
+    async () => {
+      await writeFile("some/path", "some data", "hex");
+    },
+    Error,
+    `Not implemented: "hex" encoding`
+  );
+  assertThrowsAsync(
+    async () => {
+      await writeFile("some/path", "some data", {
+        encoding: "base64",
+      });
+    },
+    Error,
+    `Not implemented: "base64" encoding`
+  );
+});
+
+test("Data is written to correct rid", async function testCorrectWriteUsingRid() {
+  const tempFile: string = await Deno.makeTempFile();
+  const file: Deno.File = await Deno.open(tempFile, {
+    create: true,
+    write: true,
+    read: true,
+  });
+
+  await writeFile(file.rid, "hello world");
+  Deno.close(file.rid);
+
+  const data = await Deno.readFile(tempFile);
+  await Deno.remove(tempFile);
+  assertEquals(decoder.decode(data), "hello world");
+});
+
+test("Data is written to correct file", async function testCorrectWriteUsingPath() {
+  const openResourcesBeforeWrite: Deno.ResourceMap = Deno.resources();
+
+  await writeFile("_fs_writeFile_test_file.txt", "hello world");
+
+  assertEquals(Deno.resources(), openResourcesBeforeWrite);
+  const data = await Deno.readFile("_fs_writeFile_test_file.txt");
+  await Deno.remove("_fs_writeFile_test_file.txt");
+  assertEquals(decoder.decode(data), "hello world");
+});
+
+test("Mode is correctly set", async function testCorrectFileMode() {
+  if (Deno.build.os === "windows") return;
+  const filename = "_fs_writeFile_test_file.txt";
+  await writeFile(filename, "hello world", { mode: 0o777 });
+
+  const fileInfo = await Deno.stat(filename);
+  await Deno.remove(filename);
+  assert(fileInfo && fileInfo.mode);
+  assertEquals(fileInfo.mode & 0o777, 0o777);
+});
+
+test("Mode is not set when rid is passed", async function testCorrectFileModeRid() {
+  if (Deno.build.os === "windows") return;
+
+  const filename: string = await Deno.makeTempFile();
+  const file: Deno.File = await Deno.open(filename, {
+    create: true,
+    write: true,
+    read: true,
+  });
+
+  await writeFile(file.rid, "hello world", { mode: 0o777 });
+  Deno.close(file.rid);
+
+  const fileInfo = await Deno.stat(filename);
+  await Deno.remove(filename);
+  assert(fileInfo.mode);
+  assertNotEquals(fileInfo.mode & 0o777, 0o777);
+});
+
+test("Mode is not implemented on windows", function testModeNotImplementedWindows(): void {
+  if (Deno.build.os !== "windows") return;
+
+  assertThrowsAsync(
+    async () => {
+      await writeFile("fail.txt", "some data", { mode: 0o777 });
+    },
+    Error,
+    `Not implemented: "mode" on Windows`
+  );
+});
diff --git a/std/node/_fs/promises/mod.ts b/std/node/_fs/promises/mod.ts
new file mode 100644
index 000000000..3cb81a422
--- /dev/null
+++ b/std/node/_fs/promises/mod.ts
@@ -0,0 +1 @@
+export { writeFile } from "./_fs_writeFile.ts";