Stream.toStreamable

• 值：Symbol.for('Stream.toStreamable')

该值必须是一个函数，能够同步地将对象转换为可流式传输的值。当在流式管道中任何地方遇到该对象时（作为传递给 fromSync() 的源，或作为从同步转换返回的值），将调用此方法以生成实际数据。它必须同步返回一个可流式传输的值：字符串、Uint8Array 或 Iterable。

🌐 The value must be a function that synchronously converts the object into a streamable value. When the object is encountered anywhere in the streaming pipeline (as a source passed to fromSync(), or as a value returned from a sync transform), this method is called to produce the actual data. It must synchronously return a streamable value: a string, Uint8Array, or Iterable.

import { fromSync, textSync } from 'node:stream/iter';

class Greeting {
  #name;

  constructor(name) {
    this.#name = name;
  }

  [Symbol.for('Stream.toStreamable')]() {
    return `hello ${this.#name}`;
  }
}

const stream = fromSync(new Greeting('world'));
console.log(textSync(stream)); // 'hello world'const { fromSync, textSync } = require('node:stream/iter');

class Greeting {
  #name;

  constructor(name) {
    this.#name = name;
  }

  [Symbol.for('Stream.toStreamable')]() {
    return `hello ${this.#name}`;
  }
}

const stream = fromSync(new Greeting('world'));
console.log(textSync(stream)); // 'hello world'拷贝