nstdlib-nightly/lib/internal/webstreams/compression.mjs

Node.js standard library converted to runtime-agnostic ES modules.

// Source: https://github.com/nodejs/node/blob/65eff1eb/lib/internal/webstreams/compression.js

import { newReadableWritablePairFromDuplex } from "nstdlib/lib/internal/webstreams/adapters";
import { customInspect } from "nstdlib/lib/internal/webstreams/util";
import {
  customInspectSymbol as kInspect,
  kEnumerableProperty,
} from "nstdlib/lib/internal/util";
import { createEnumConverter } from "nstdlib/lib/internal/webidl";
import * as __hoisted_zlib__ from "nstdlib/lib/zlib";

let zlib;
function lazyZlib() {
  zlib ??= __hoisted_zlib__;
  return zlib;
}

const formatConverter = createEnumConverter("CompressionFormat", [
  "deflate",
  "deflate-raw",
  "gzip",
]);

/**
 * @typedef {import('./readablestream').ReadableStream} ReadableStream
 * @typedef {import('./writablestream').WritableStream} WritableStream
 */

class CompressionStream {
  #handle;
  #transform;

  /**
   * @param {'deflate'|'deflate-raw'|'gzip'} format
   */
  constructor(format) {
    format = formatConverter(format, {
      prefix: "Failed to construct 'CompressionStream'",
      context: "1st argument",
    });
    switch (format) {
      case "deflate":
        this.#handle = lazyZlib().createDeflate();
        break;
      case "deflate-raw":
        this.#handle = lazyZlib().createDeflateRaw();
        break;
      case "gzip":
        this.#handle = lazyZlib().createGzip();
        break;
    }
    this.#transform = newReadableWritablePairFromDuplex(this.#handle);
  }

  /**
   * @readonly
   * @type {ReadableStream}
   */
  get readable() {
    return this.#transform.readable;
  }

  /**
   * @readonly
   * @type {WritableStream}
   */
  get writable() {
    return this.#transform.writable;
  }

  [kInspect](depth, options) {
    return customInspect(depth, options, "CompressionStream", {
      readable: this.#transform.readable,
      writable: this.#transform.writable,
    });
  }
}

class DecompressionStream {
  #handle;
  #transform;

  /**
   * @param {'deflate'|'deflate-raw'|'gzip'} format
   */
  constructor(format) {
    format = formatConverter(format, {
      prefix: "Failed to construct 'DecompressionStream'",
      context: "1st argument",
    });
    switch (format) {
      case "deflate":
        this.#handle = lazyZlib().createInflate();
        break;
      case "deflate-raw":
        this.#handle = lazyZlib().createInflateRaw();
        break;
      case "gzip":
        this.#handle = lazyZlib().createGunzip();
        break;
    }
    this.#transform = newReadableWritablePairFromDuplex(this.#handle);
  }

  /**
   * @readonly
   * @type {ReadableStream}
   */
  get readable() {
    return this.#transform.readable;
  }

  /**
   * @readonly
   * @type {WritableStream}
   */
  get writable() {
    return this.#transform.writable;
  }

  [kInspect](depth, options) {
    return customInspect(depth, options, "DecompressionStream", {
      readable: this.#transform.readable,
      writable: this.#transform.writable,
    });
  }
}

Object.defineProperties(CompressionStream.prototype, {
  readable: kEnumerableProperty,
  writable: kEnumerableProperty,
  [Symbol.toStringTag]: {
    __proto__: null,
    configurable: true,
    value: "CompressionStream",
  },
});

Object.defineProperties(DecompressionStream.prototype, {
  readable: kEnumerableProperty,
  writable: kEnumerableProperty,
  [Symbol.toStringTag]: {
    __proto__: null,
    configurable: true,
    value: "DecompressionStream",
  },
});

export { CompressionStream };
export { DecompressionStream };