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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** Options for {@linkcode TextLineStream}. */export interface TextLineStreamOptions {  /**   * Allow splitting by `\r`.   *   * @default {false}   */  allowCR?: boolean;}
/** * Transform a stream into a stream where each chunk is divided by a newline, * be it `\n` or `\r\n`. `\r` can be enabled via the `allowCR` option. * * @example * ```ts * import { TextLineStream } from "https://deno.land/std@$STD_VERSION/streams/text_line_stream.ts"; * * const res = await fetch("https://example.com"); * const lines = res.body! *   .pipeThrough(new TextDecoderStream()) *   .pipeThrough(new TextLineStream()); * ``` */export class TextLineStream extends TransformStream<string, string> {  #currentLine = "";
  /** Constructs a new instance. */  constructor(options: TextLineStreamOptions = { allowCR: false }) {    super({      transform: (chars, controller) => {        chars = this.#currentLine + chars;
        while (true) {          const lfIndex = chars.indexOf("\n");          const crIndex = options.allowCR ? chars.indexOf("\r") : -1;
          if (            crIndex !== -1 && crIndex !== (chars.length - 1) &&            (lfIndex === -1 || (lfIndex - 1) > crIndex)          ) {            controller.enqueue(chars.slice(0, crIndex));            chars = chars.slice(crIndex + 1);            continue;          }
          if (lfIndex === -1) break;
          const endIndex = chars[lfIndex - 1] === "\r" ? lfIndex - 1 : lfIndex;          controller.enqueue(chars.slice(0, endIndex));          chars = chars.slice(lfIndex + 1);        }
        this.#currentLine = chars;      },      flush: (controller) => {        if (this.#currentLine === "") return;        const currentLine = options.allowCR && this.#currentLine.endsWith("\r")          ? this.#currentLine.slice(0, -1)          : this.#currentLine;        controller.enqueue(currentLine);      },    });  }}