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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
import type { Writer, WriterSync } from "./types.d.ts";
const decoder = new TextDecoder();
/** * Writer utility for buffering string chunks. * * @example * ```ts * import { *   copyN, *   StringReader, *   StringWriter, * } from "https://deno.land/std@$STD_VERSION/io/mod.ts"; * import { copy } from "https://deno.land/std@$STD_VERSION/streams/copy.ts"; * * const w = new StringWriter("base"); * const r = new StringReader("0123456789"); * await copyN(r, w, 4); // copy 4 bytes * * // Number of bytes read * console.log(w.toString()); //base0123 * * await copy(r, w); // copy all * console.log(w.toString()); // base0123456789 * ``` * * **Output:** * * ```text * base0123 * base0123456789 * ``` */export class StringWriter implements Writer, WriterSync {  #chunks: Uint8Array[] = [];  #byteLength = 0;  #cache: string | undefined;
  constructor(private base: string = "") {    const c = new TextEncoder().encode(base);    this.#chunks.push(c);    this.#byteLength += c.byteLength;  }
  write(p: Uint8Array): Promise<number> {    return Promise.resolve(this.writeSync(p));  }
  writeSync(p: Uint8Array): number {    this.#chunks.push(new Uint8Array(p));    this.#byteLength += p.byteLength;    this.#cache = undefined;    return p.byteLength;  }
  toString(): string {    if (this.#cache) {      return this.#cache;    }    const buf = new Uint8Array(this.#byteLength);    let offs = 0;    for (const chunk of this.#chunks) {      buf.set(chunk, offs);      offs += chunk.byteLength;    }    this.#cache = decoder.decode(buf);    return this.#cache;  }}