ReactServerStreamConfigNode.js — react Source File

Source Code

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow
 */

import type {Writable} from 'stream';

import {TextEncoder} from 'util';
import {createHash} from 'crypto';

interface MightBeFlushable {
  flush?: () => void;
}

export type Destination = Writable & MightBeFlushable;

export type PrecomputedChunk = Uint8Array;
export opaque type Chunk = string;
export type BinaryChunk = Uint8Array;

export function scheduleWork(callback: () => void) {
  setImmediate(callback);
}

export const scheduleMicrotask = queueMicrotask;

export function flushBuffered(destination: Destination) {
  // If we don't have any more data to send right now.
  // Flush whatever is in the buffer to the wire.
  if (typeof destination.flush === 'function') {
    // By convention the Zlib streams provide a flush function for this purpose.
    // For Express, compression middleware adds this method.
    destination.flush();
  }
}

// Chunks larger than VIEW_SIZE are written directly, without copying into the
// internal view buffer. This must be at least half of Node's internal Buffer
// pool size (8192) to avoid corrupting the pool when using
// renderToReadableStream, which uses a byte stream that detaches ArrayBuffers.
const VIEW_SIZE = 4096;
let currentView = null;
let writtenBytes = 0;
let destinationHasCapacity = true;

export function beginWriting(destination: Destination) {
  currentView = new Uint8Array(VIEW_SIZE);
  writtenBytes = 0;
  destinationHasCapacity = true;
}

function writeStringChunk(destination: Destination, stringChunk: string) {
  if (stringChunk.length === 0) {
    return;
  }
  // maximum possible view needed to encode entire string
// ... (191 more lines)