node.ts

export * from './index.js';

import type { CheerioAPI, CheerioOptions } from './index.js';
import { load } from './index.js';
import { flatten as flattenOptions } from './options.js';
import { adapter as htmlparser2Adapter } from 'parse5-htmlparser2-tree-adapter';

// eslint-disable-next-line node/file-extension-in-import
import { WritableStream as Htmlparser2Stream } from 'htmlparser2/lib/WritableStream';
import DomHandler from 'domhandler';
import { ParserStream as Parse5Stream } from 'parse5-parser-stream';
import { DecodeStream } from 'encoding-sniffer';
import * as undici from 'undici';
import { type Writable, finished } from 'node:stream';

export function stringStream(
  options: CheerioOptions,
  cb: (err: Error | null | undefined, $: CheerioAPI) => void
): Writable {
  const opts = flattenOptions(options);

  if (opts && (opts.xmlMode || opts._useHtmlParser2)) {
    const handler: DomHandler = new DomHandler(
      (err) => cb(err, load(handler.root)),
      opts
    );

    return new Htmlparser2Stream(handler, opts);
  }

  const stream = new Parse5Stream({ ...opts, treeAdapter: htmlparser2Adapter });

  finished(stream, (err) => cb(err, load(stream.document)));

  return stream;
}

export function decodeStream(
  options: CheerioOptions,
  cb: (err: Error | null | undefined, $: CheerioAPI) => void
): Writable {
  // TODO: Set the encoding to UTF8 for XML mode
  const decodeStream = new DecodeStream();
  const loadStream = stringStream(options, cb);

  decodeStream.pipe(loadStream);

  return decodeStream;
}

// Get a document from a URL
export async function request(
  // eslint-disable-next-line node/no-unsupported-features/node-builtins
  url: string | URL,
  options: CheerioOptions
): Promise<CheerioAPI> {
  let undiciStream: Promise<undici.Dispatcher.StreamData> | undefined;

  const promise = new Promise<CheerioAPI>((resolve, reject) => {
    undiciStream = undici.stream(
      url,
      {
        method: 'GET',
        headers: {
          'user-agent':
            'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36',
        },
      },
      (data) => {
        // TODO Add support for handling status codes.
        if (!data.statusCode) {
          throw new Error(`Received ${data.statusCode}`);
        }

        // TODO: Forward the charset from the header to the decodeStream.
        return decodeStream(options, (err, $) =>
          err ? reject(err) : resolve($)
        );
      }
    );
  });

  // Let's make sure the request is completed before returning the promise.
  await undiciStream;

  return promise;
}