buffer: add blob endings option, remove Node.js specific encoding option

doc/api/buffer.md

@@ -459,14 +459,20 @@ multiple worker threads.
 ### `new buffer.Blob([sources[, options]])`
 <!-- YAML
 added: v15.7.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/39708
+    description: Added the standard `endings` option to replace line-endings,
+                 and removed the non-standard `encoding` option.
 -->
 
 * `sources` {string[]|ArrayBuffer[]|TypedArray[]|DataView[]|Blob[]} An array
   of string, {ArrayBuffer}, {TypedArray}, {DataView}, or {Blob} objects, or
   any mix of such objects, that will be stored within the `Blob`.
 * `options` {Object}
-  * `encoding` {string} The character encoding to use for string sources.
-    **Default:** `'utf8'`.
+  * `endings` {string} One of either `'transparent'` or `'native'`. When set
+    to `'native'`, line endings in string source parts will be converted to
+    the platform native line-ending as specified by `require('os').EOL`.
   * `type` {string} The Blob content-type. The intent is for `type` to convey
     the MIME media type of the data, however no validation of the type format
     is performed.
@@ -476,7 +482,9 @@ Creates a new `Blob` object containing a concatenation of the given sources.
 {ArrayBuffer}, {TypedArray}, {DataView}, and {Buffer} sources are copied into
 the 'Blob' and can therefore be safely modified after the 'Blob' is created.
 
-String sources are also copied into the `Blob`.
+String sources are encoded as UTF-8 byte sequences and copied into the Blob.
+Unmatched surrogate pairs within each string part will be replaced by Unicode
+U+FFFD replacement characters.
 
 ### `blob.arrayBuffer()`
 <!-- YAML

lib/internal/blob.js

@@ -9,6 +9,7 @@ const {
   PromiseReject,
   SafePromisePrototypeFinally,
   ReflectConstruct,
+  RegExpPrototypeSymbolReplace,
   RegExpPrototypeTest,
   StringPrototypeToLowerCase,
   StringPrototypeSplit,
@@ -24,7 +25,10 @@ const {
   getDataObject,
 } = internalBinding('blob');
 
-const { TextDecoder } = require('internal/encoding');
+const {
+  TextDecoder,
+  TextEncoder,
+} = require('internal/encoding');
 
 const {
   makeTransferable,
@@ -48,6 +52,7 @@ const {
   AbortError,
   codes: {
     ERR_INVALID_ARG_TYPE,
+    ERR_INVALID_ARG_VALUE,
     ERR_INVALID_THIS,
     ERR_BUFFER_TOO_LARGE,
   }
@@ -68,10 +73,11 @@ const kMaxChunkSize = 65536;
 
 const disallowedTypeCharacters = /[^\u{0020}-\u{007E}]/u;
 
-let Buffer;
 let ReadableStream;
 let URL;
+let EOL;
 
+const enc = new TextEncoder();
 
 // Yes, lazy loading is annoying but because of circular
 // references between the url, internal/blob, and buffer
@@ -82,29 +88,35 @@ function lazyURL(id) {
   return new URL(id);
 }
 
-function lazyBuffer() {
-  Buffer ??= require('buffer').Buffer;
-  return Buffer;
-}
-
 function lazyReadableStream(options) {
   ReadableStream ??=
     require('internal/webstreams/readablestream').ReadableStream;
   return new ReadableStream(options);
 }
 
+// TODO(@jasnell): This is annoying but this has to be lazy because
+// requiring the 'os' module too early causes building Node.js to
+// fail with an unknown reference failure.
+function lazyEOL() {
+  EOL ??= require('os').EOL;
+  return EOL;
+}
+
 function isBlob(object) {
   return object?.[kHandle] !== undefined;
 }
 
-function getSource(source, encoding) {
+function getSource(source, endings) {
   if (isBlob(source))
     return [source.size, source[kHandle]];
 
   if (isAnyArrayBuffer(source)) {
     source = new Uint8Array(source);
   } else if (!isArrayBufferView(source)) {
-    source = lazyBuffer().from(`${source}`, encoding);
+    source = `${source}`;
+    if (endings === 'native')
+      source = RegExpPrototypeSymbolReplace(/\n|\r\n/g, source, lazyEOL());
+    source = enc.encode(source);
   }
 
   // We copy into a new Uint8Array because the underlying
@@ -116,6 +128,16 @@ function getSource(source, encoding) {
 }
 
 class Blob {
+  /**
+   * @typedef {string|ArrayBuffer|ArrayBufferView|Blob} SourcePart
+   *
+   * @param {SourcePart[]} [sources]
+   * @param {{
+   *   endings? : string,
+   *   type? : string,
+   * }} [options]
+   * @returns
+   */
   constructor(sources = [], options = {}) {
     emitExperimentalWarning('buffer.Blob');
     if (sources === null ||
@@ -124,12 +146,18 @@ class Blob {
       throw new ERR_INVALID_ARG_TYPE('sources', 'Iterable', sources);
     }
     validateObject(options, 'options');
-    const { encoding = 'utf8' } = options;
-    let { type = '' } = options;
+    let {
+      type = '',
+      endings = 'transparent',
+    } = options;
+
+    endings = `${endings}`;
+    if (endings !== 'transparent' && endings !== 'native')
+      throw new ERR_INVALID_ARG_VALUE('options.endings', endings);
 
     let length = 0;
     const sources_ = ArrayFrom(sources, (source) => {
-      const { 0: len, 1: src } = getSource(source, encoding);
+      const { 0: len, 1: src } = getSource(source, endings);
       length += len;
       return src;
     });

test/parallel/test-blob.js

@@ -1,9 +1,11 @@
+// Flags: --no-warnings
 'use strict';
 
 const common = require('../common');
 const assert = require('assert');
 const { Blob } = require('buffer');
 const { inspect } = require('util');
+const { EOL } = require('os');
 
 {
   const b = new Blob();
@@ -45,15 +47,6 @@ assert.throws(() => new Blob({}), {
   assert.strictEqual(new Blob([], { type: {} }).type, '[object object]');
 }
 
-{
-  const b = new Blob(['616263'], { encoding: 'hex', type: 'foo' });
-  assert.strictEqual(b.size, 3);
-  assert.strictEqual(b.type, 'foo');
-  b.text().then(common.mustCall((text) => {
-    assert.strictEqual(text, 'abc');
-  }));
-}
-
 {
   const b = new Blob([Buffer.from('abc')]);
   assert.strictEqual(b.size, 3);
@@ -216,3 +209,14 @@ assert.throws(() => new Blob({}), {
   res = await reader.read();
   assert(res.done);
 })().then(common.mustCall());
+
+{
+  const b = new Blob(['hello\n'], { endings: 'native' });
+  assert.strictEqual(b.size, EOL.length + 5);
+
+  [1, {}, 'foo'].forEach((endings) => {
+    assert.throws(() => new Blob([], { endings }), {
+      code: 'ERR_INVALID_ARG_VALUE',
+    });
+  });
+}