Replace Buffer with Uint8Array

lib/snapshot-manager.js

@@ -1,4 +1,3 @@
-import {Buffer} from 'node:buffer';
 import crypto from 'node:crypto';
 import fs from 'node:fs';
 import {findSourceMap} from 'node:module';
@@ -16,17 +15,17 @@
 import slash from './slash.cjs';
 
 // Increment if encoding layout or Concordance serialization versions change. Previous AVA versions will not be able to
-// decode buffers generated by a newer version, so changing this value will require a major version bump of AVA itself.
+// decode byte arrays generated by a newer version, so changing this value will require a major version bump of AVA itself.
 // The version is encoded as an unsigned 16 bit integer.
 const VERSION = 3;
 
-const VERSION_HEADER = Buffer.alloc(2);
-VERSION_HEADER.writeUInt16LE(VERSION);
+const VERSION_HEADER = new Uint8Array(2);
+new DataView(VERSION_HEADER).setUint16(0, VERSION, true);
 
 // The decoder matches on the trailing newline byte (0x0A).
-const READABLE_PREFIX = Buffer.from(`AVA Snapshot v${VERSION}\n`, 'ascii');
-const REPORT_SEPARATOR = Buffer.from('\n\n', 'ascii');
-const REPORT_TRAILING_NEWLINE = Buffer.from('\n', 'ascii');
+const READABLE_PREFIX = new TextEncoder().encode(`AVA Snapshot v${VERSION}\n`);
+const REPORT_SEPARATOR = new TextEncoder().encode('\n\n');
+const REPORT_TRAILING_NEWLINE = new TextEncoder().encode('\n');
 
 const SHA_256_HASH_LENGTH = 32;
 
@@ -61,9 +60,9 @@
 	}
 }
 
-const LEGACY_SNAPSHOT_HEADER = Buffer.from('// Jest Snapshot v1');
-function isLegacySnapshot(buffer) {
-	return LEGACY_SNAPSHOT_HEADER.equals(buffer.slice(0, LEGACY_SNAPSHOT_HEADER.byteLength));
+const LEGACY_SNAPSHOT_HEADER = new TextEncoder().encode('// Jest Snapshot v1');
+function isLegacySnapshot(array) {
+	return LEGACY_SNAPSHOT_HEADER.equals(array.subarray(0, LEGACY_SNAPSHOT_HEADER.byteLength));
 }
 
 export class LegacyError extends SnapshotError {
@@ -101,7 +100,7 @@
 }
 
 function combineEntries({blocks}) {
-	const combined = new BufferBuilder();
+	const combined = new Uint8ArrayBuilder();
 
 	for (const {title, snapshots} of blocks) {
 		const last = snapshots.at(-1);
@@ -120,42 +119,43 @@
 }
 
 function generateReport(relFile, snapFile, snapshots) {
-	return new BufferBuilder()
+	return new Uint8ArrayBuilder()
 		.write(`# Snapshot report for \`${slash(relFile)}\`
 
 The actual snapshot is saved in \`${snapFile}\`.
 
 Generated by [AVA](https://avajs.dev).`)
 		.append(combineEntries(snapshots))
 		.write(REPORT_TRAILING_NEWLINE)
-		.toBuffer();
+		.toUint8Array();
 }
 
-class BufferBuilder {
+class Uint8ArrayBuilder {
 	constructor() {
-		this.buffers = [];
+		this.arrays = [];
 		this.byteOffset = 0;
 	}
 
 	append(builder) {
-		this.buffers.push(...builder.buffers);
+		this.arrays.push(...builder.arrays);
 		this.byteOffset += builder.byteOffset;
 		return this;
 	}
 
 	write(data) {
 		if (typeof data === 'string') {
-			this.write(Buffer.from(data, 'utf8'));
+			const encoder = new TextEncoder();
+			this.write(encoder.encode(data));
 		} else {
-			this.buffers.push(data);
+			this.arrays.push(data);
 			this.byteOffset += data.byteLength;
 		}
 
 		return this;
 	}
 
-	toBuffer() {
-		return Buffer.concat(this.buffers, this.byteOffset);
+	toUint8Array() {
+		return concatUint8Arrays(this.arrays, this.byteOffset);
 	}
 }
 
@@ -190,46 +190,47 @@
 	const compressed = zlib.gzipSync(encoded);
 	compressed[9] = 0x03; // Override the GZip header containing the OS to always be Linux
 	const sha256sum = crypto.createHash('sha256').update(compressed).digest();
-	return Buffer.concat([
+	return concatUint8Arrays([
 		READABLE_PREFIX,
 		VERSION_HEADER,
 		sha256sum,
 		compressed,
 	], READABLE_PREFIX.byteLength + VERSION_HEADER.byteLength + SHA_256_HASH_LENGTH + compressed.byteLength);
 }
 
-export function extractCompressedSnapshot(buffer, snapPath) {
-	if (isLegacySnapshot(buffer)) {
+export function extractCompressedSnapshot(array, snapPath) {
+	if (isLegacySnapshot(array)) {
 		throw new LegacyError(snapPath);
 	}
 
 	// The version starts after the readable prefix, which is ended by a newline
 	// byte (0x0A).
-	const newline = buffer.indexOf(0x0A);
+	const newline = array.indexOf(0x0A);
 	if (newline === -1) {
 		throw new InvalidSnapshotError(snapPath);
 	}
 
+	const view = new DataView(array);
 	const versionOffset = newline + 1;
-	const version = buffer.readUInt16LE(versionOffset);
+	const version = view.getUint16(versionOffset, true);
 	if (version !== VERSION) {
 		throw new VersionMismatchError(snapPath, version);
 	}
 
 	const sha256sumOffset = versionOffset + 2;
 	const compressedOffset = sha256sumOffset + SHA_256_HASH_LENGTH;
-	const compressed = buffer.slice(compressedOffset);
+	const compressed = array.subarray(compressedOffset);
 
 	return {
 		version, compressed, sha256sumOffset, compressedOffset,
 	};
 }
 
-function decodeSnapshots(buffer, snapPath) {
-	const {compressed, sha256sumOffset, compressedOffset} = extractCompressedSnapshot(buffer, snapPath);
+function decodeSnapshots(array, snapPath) {
+	const {compressed, sha256sumOffset, compressedOffset} = extractCompressedSnapshot(array, snapPath);
 
 	const sha256sum = crypto.createHash('sha256').update(compressed).digest();
-	const expectedSum = buffer.slice(sha256sumOffset, compressedOffset);
+	const expectedSum = array.subarray(sha256sumOffset, compressedOffset);
 	if (!sha256sum.equals(expectedSum)) {
 		throw new ChecksumError(snapPath);
 	}
@@ -373,16 +374,16 @@
 			),
 		};
 
-		const buffer = await encodeSnapshots(snapshots);
-		const reportBuffer = generateReport(relFile, snapFile, snapshots);
+		const array = await encodeSnapshots(snapshots);
+		const reportArray = generateReport(relFile, snapFile, snapshots);
 
 		await fs.promises.mkdir(dir, {recursive: true});
 
 		const temporaryFiles = [];
 		const tmpfileCreated = file => temporaryFiles.push(file);
 		await Promise.all([
-			writeFileAtomic(snapPath, buffer, {tmpfileCreated}),
-			writeFileAtomic(reportPath, reportBuffer, {tmpfileCreated}),
+			writeFileAtomic(snapPath, array, {tmpfileCreated}),
+			writeFileAtomic(reportPath, reportArray, {tmpfileCreated}),
 		]);
 		return {
 			changedFiles: [snapPath, reportPath],
@@ -470,9 +471,9 @@
 	}
 
 	const paths = determineSnapshotPaths({file, fixedLocation, projectDir});
-	const buffer = tryRead(paths.snapPath);
+	const array = tryRead(paths.snapPath);
 
-	if (!buffer) {
+	if (!array) {
 		return new Manager({
 			recordNewSnapshots,
 			updating,
@@ -486,7 +487,7 @@
 	let snapshotError;
 
 	try {
-		const data = decodeSnapshots(buffer, paths.snapPath);
+		const data = decodeSnapshots(array, paths.snapPath);
 		blocksByTitle = new Map(data.blocks.map(({title, ...block}) => [title, block]));
 	} catch (error) {
 		blocksByTitle = new Map();

media/screenshot-fixtures/magic-assert-buffers.js

@@ -1,7 +1,8 @@
 import test from 'ava';
+import {hexToUint8Array} from 'uint8array-extras';
 
 test('buffers', t => {
-	const actual = Buffer.from('decafbadcab00d1e'.repeat(4), 'hex')
-	const expected = Buffer.from('cab00d1edecafbad' + 'decafbadcab00d1e'.repeat(3), 'hex')
+	const actual = hexToUint8Array('decafbadcab00d1e'.repeat(4))
+	const expected = hexToUint8Array('cab00d1edecafbad' + 'decafbadcab00d1e'.repeat(3))
 	t.deepEqual(actual, expected)
 });

package.json

@@ -121,6 +121,7 @@
 		"strip-ansi": "^7.1.0",
 		"supertap": "^3.0.1",
 		"temp-dir": "^3.0.0",
+		"uint8array-extras": "^1.1.0",
 		"write-file-atomic": "^5.0.1",
 		"yargs": "^17.7.2"
 	},

test-tap/helper/report.js

@@ -7,26 +7,27 @@
 import Api from '../../lib/api.js';
 import {_testOnlyReplaceWorkerPath} from '../../lib/fork.js';
 import {normalizeGlobs} from '../../lib/globs.js';
 import pkg from '../../lib/pkg.cjs';
+import {uint8ArrayToString} from 'uint8array-extras';
 
 _testOnlyReplaceWorkerPath(new URL('report-worker.js', import.meta.url));
 
 const exports = {};
 export default exports;
 
-exports.assert = (t, logFile, buffer) => {
+exports.assert = (t, logFile, array) => {
 	let existing = null;
 	try {
 		existing = fs.readFileSync(logFile);
 	} catch {}
 
 	if (existing === null || process.env.UPDATE_REPORTER_LOG) {
-		fs.writeFileSync(logFile, buffer);
-		existing = buffer;
+		fs.writeFileSync(logFile, array);
+		existing = array;
 	}
 
-	const expected = existing.toString('utf8');
-	const actual = buffer.toString('utf8');
+	const expected = uint8ArrayToString(existing);
+	const actual = uint8ArrayToString(array);
 	if (actual === expected) {
 		t.pass();
 	} else {

test-tap/helper/tty-stream.js

@@ -1,7 +1,7 @@
-import {Buffer} from 'node:buffer';
 import stream from 'node:stream';
 
 import ansiEscapes from 'ansi-escapes';
+import {stringToUint8Array, concatUint8Arrays, uint8ArrayToString} from 'uint8array-extras';
 
 export default class TTYStream extends stream.Writable {
 	constructor(options) {
@@ -17,7 +17,7 @@
 
 	_write(chunk, encoding, callback) {
 		if (this.spinnerActivity.length > 0) {
-			this.chunks.push(Buffer.concat(this.spinnerActivity), TTYStream.SEPARATOR);
+			this.chunks.push(concatUint8Arrays(this.spinnerActivity), TTYStream.SEPARATOR);
 			this.spinnerActivity = [];
 		}
 
@@ -26,7 +26,7 @@
 		// chunks.
 		if (string !== '' || chunk.length === 0) {
 			this.chunks.push(
-				Buffer.from(string, 'utf8'),
+				stringToUint8Array(string),
 				TTYStream.SEPARATOR,
 			);
 		}
@@ -36,33 +36,37 @@
 
 	_writev(chunks, callback) {
 		if (this.spinnerActivity.length > 0) {
-			this.chunks.push(Buffer.concat(this.spinnerActivity), TTYStream.SEPARATOR);
+			this.chunks.push(concatUint8Arrays(this.spinnerActivity), TTYStream.SEPARATOR);
 			this.spinnerActivity = [];
 		}
 
 		for (const object of chunks) {
-			this.chunks.push(Buffer.from(this.sanitizers.reduce((string, sanitizer) => sanitizer(string), object.chunk.toString('utf8')), 'utf8')); // eslint-disable-line unicorn/no-array-reduce
+			this.chunks.push(stringToUint8Array(this.sanitizers.reduce((string, sanitizer) => sanitizer(string), uint8ArrayToString(object.chunk)))); // eslint-disable-line unicorn/no-array-reduce
 		}
 
 		this.chunks.push(TTYStream.SEPARATOR);
 		callback();
 	}
 
-	asBuffer() {
-		return Buffer.concat(this.chunks);
+	asUint8Array() {
+		return concatUint8Arrays(this.chunks);
+	}
+
+	toString() {
+		return uint8ArrayToString(array);
 	}
 
 	clearLine() {
-		this.spinnerActivity.push(Buffer.from(ansiEscapes.eraseLine, 'ascii'));
+		this.spinnerActivity.push(stringToUint8Array(ansiEscapes.eraseLine));
 	}
 
 	cursorTo(x, y) {
-		this.spinnerActivity.push(Buffer.from(ansiEscapes.cursorTo(x, y), 'ascii'));
+		this.spinnerActivity.push(stringToUint8Array(ansiEscapes.cursorTo(x, y)));
 	}
 
 	moveCursor(dx, dy) {
-		this.spinnerActivity.push(Buffer.from(ansiEscapes.cursorMove(dx, dy), 'ascii'));
+		this.spinnerActivity.push(stringToUint8Array(ansiEscapes.cursorMove(dx, dy)));
 	}
 }
 
-TTYStream.SEPARATOR = Buffer.from('---tty-stream-chunk-separator\n', 'utf8');
+TTYStream.SEPARATOR = stringToUint8Array('---tty-stream-chunk-separator\n');