doc,test: widen fsPromises.appendFile()'s data type, add missing tests

doc/api/fs.md

@@ -1241,7 +1241,7 @@ changes:
 -->
 
 * `path` {string|Buffer|URL|FileHandle} filename or {FileHandle}
-* `data` {string|Buffer}
+* `data` {string|Buffer|TypedArray|DataView|AsyncIterable|Iterable|Stream}
 * `options` {Object|string}
   * `encoding` {string|null} **Default:** `'utf8'`
   * `mode` {integer} **Default:** `0o666`
@@ -1251,7 +1251,7 @@ changes:
 * Returns: {Promise} Fulfills with `undefined` upon success.
 
 Asynchronously append data to a file, creating the file if it does not yet
-exist. `data` can be a string or a {Buffer}.
+`data` can be a string, a buffer, an {AsyncIterable}, or an {Iterable} object.
 
 If `options` is a string, then it specifies the `encoding`.
 

test/parallel/test-fs-promises-appendfile.js

@@ -0,0 +1,191 @@
+'use strict';
+
+const common = require('../common');
+const fs = require('fs');
+const fsPromises = fs.promises;
+const path = require('path');
+const tmpdir = require('../common/tmpdir');
+const assert = require('assert');
+const tmpDir = tmpdir.path;
+const { Readable } = require('stream');
+
+tmpdir.refresh();
+
+const buffer = Buffer.from('abc'.repeat(1000));
+const stream = Readable.from(['a', 'b', 'c']);
+const stream2 = Readable.from(['ümlaut', ' ', 'sechzig']);
+const iterable = {
+  expected: 'abc',
+  *[Symbol.iterator]() {
+    yield 'a';
+    yield 'b';
+    yield 'c';
+  }
+};
+
+const veryLargeIterable = {
+  expected: 'dogs running'.repeat(512 * 1024),
+  *[Symbol.iterator]() {
+    yield Buffer.from('dogs running'.repeat(512 * 1024), 'utf8');
+  }
+};
+
+function iterableWith(value) {
+  return {
+    *[Symbol.iterator]() {
+      yield value;
+    }
+  };
+}
+const bufferIterable = {
+  expected: 'abc',
+  *[Symbol.iterator]() {
+    yield Buffer.from('a');
+    yield Buffer.from('b');
+    yield Buffer.from('c');
+  }
+};
+const asyncIterable = {
+  expected: 'abc',
+  async* [Symbol.asyncIterator]() {
+    yield 'a';
+    yield 'b';
+    yield 'c';
+  }
+};
+
+let counter = 0;
+
+async function doAppendString() {
+  const string = 'x~yz'.repeat(100);
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  await fsPromises.appendFile(dest, string);
+  const data = fs.readFileSync(dest);
+  const stringAsBuffer = Buffer.from(string, 'utf8');
+  assert.deepStrictEqual(stringAsBuffer, data);
+}
+
+async function doAppendBuffer() {
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  await fsPromises.appendFile(dest, buffer);
+  const data = fs.readFileSync(dest);
+  assert.deepStrictEqual(data, buffer);
+}
+
+async function doAppendStream() {
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  await fsPromises.appendFile(dest, stream);
+  const expected = 'abc';
+  const data = fs.readFileSync(dest, 'utf-8');
+  assert.deepStrictEqual(data, expected);
+}
+
+async function doAppendStreamWithCancel() {
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  const controller = new AbortController();
+  const { signal } = controller;
+  process.nextTick(() => controller.abort());
+  await assert.rejects(
+    fsPromises.appendFile(dest, stream, { signal }),
+    { name: 'AbortError' }
+  );
+}
+
+async function doAppendIterable() {
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  await fsPromises.appendFile(dest, iterable);
+  const data = fs.readFileSync(dest, 'utf-8');
+  assert.deepStrictEqual(data, iterable.expected);
+}
+
+async function doAppendInvalidIterable() {
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  await Promise.all(
+    [42, 42n, {}, Symbol('42'), true, undefined, null, NaN].map((value) =>
+      assert.rejects(fsPromises.appendFile(dest, iterableWith(value)), {
+        code: 'ERR_INVALID_ARG_TYPE',
+      })
+    )
+  );
+}
+
+async function doAppendIterableWithEncoding() {
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  await fsPromises.appendFile(dest, stream2, 'latin1');
+  const expected = 'ümlaut sechzig';
+  const data = fs.readFileSync(dest, 'latin1');
+  assert.deepStrictEqual(data, expected);
+}
+
+async function doAppendBufferIterable() {
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  await fsPromises.appendFile(dest, bufferIterable);
+  const data = fs.readFileSync(dest, 'utf-8');
+  assert.deepStrictEqual(data, bufferIterable.expected);
+}
+
+async function doAppendAsyncIterable() {
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  await fsPromises.appendFile(dest, asyncIterable);
+  const data = fs.readFileSync(dest, 'utf-8');
+  assert.deepStrictEqual(data, asyncIterable.expected);
+}
+
+async function doAppendLargeIterable() {
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  await fsPromises.appendFile(dest, veryLargeIterable);
+  const data = fs.readFileSync(dest, 'utf-8');
+  assert.deepStrictEqual(data, veryLargeIterable.expected);
+}
+
+async function doAppendInvalidValues() {
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  await Promise.all(
+    [42, 42n, {}, Symbol('42'), true, undefined, null, NaN].map((value) =>
+      assert.rejects(fsPromises.appendFile(dest, value), {
+        code: 'ERR_INVALID_ARG_TYPE',
+      })
+    )
+  );
+}
+
+async function doAppendBufferAndCancel() {
+  const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+  const controller = new AbortController();
+  const { signal } = controller;
+  process.nextTick(() => controller.abort());
+  await assert.rejects(
+    fsPromises.appendFile(dest, buffer, { signal }),
+    { name: 'AbortError' }
+  );
+}
+
+async function doAppendTypedArrays() {
+  for (const Constructor of [Uint8Array, Uint16Array, Uint32Array]) {
+    const dest = path.resolve(tmpDir, `tmp-${counter++}.txt`);
+
+    // Use a file size larger than `kReadFileMaxChunkSize`.
+    const buffer = Buffer.from('012'.repeat(2 ** 14));
+
+    const array = new Constructor(buffer.buffer);
+    await fsPromises.appendFile(dest, array);
+    const data = await fsPromises.readFile(dest);
+    assert.deepStrictEqual(data, buffer);
+  }
+}
+
+(async () => {
+  await doAppendBuffer();
+  await doAppendBufferAndCancel();
+  await doAppendString();
+  await doAppendStream();
+  await doAppendStreamWithCancel();
+  await doAppendIterable();
+  await doAppendInvalidIterable();
+  await doAppendIterableWithEncoding();
+  await doAppendBufferIterable();
+  await doAppendAsyncIterable();
+  await doAppendLargeIterable();
+  await doAppendInvalidValues();
+  await doAppendTypedArrays();
+})().then(common.mustCall());