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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
/** Optional object interface for `JsonStringifyStream`. */export interface StringifyStreamOptions {  /** Prefix to be added after stringify. The default is "". */  readonly prefix?: string;  /** Suffix to be added after stringify. The default is "\n". */  readonly suffix?: string;  /** Controls the buffer of the TransformStream used internally. Check https://developer.mozilla.org/en-US/docs/Web/API/TransformStream/TransformStream. */  readonly writableStrategy?: QueuingStrategy<unknown>;  /** Controls the buffer of the TransformStream used internally. Check https://developer.mozilla.org/en-US/docs/Web/API/TransformStream/TransformStream. */  readonly readableStrategy?: QueuingStrategy<string>;}
/** * Convert each chunk to JSON string. * * This can be used to stringify [JSON lines](https://jsonlines.org/), [NDJSON](http://ndjson.org/), [JSON Text Sequences](https://datatracker.ietf.org/doc/html/rfc7464), and [Concatenated JSON](https://en.wikipedia.org/wiki/JSON_streaming#Concatenated_JSON). * You can optionally specify a prefix and suffix for each chunk. The default prefix is "" and the default suffix is "\n". * * ```ts * import { readableStreamFromIterable } from "https://deno.land/std@$STD_VERSION/streams/mod.ts"; * import { JsonStringifyStream } from "https://deno.land/std@$STD_VERSION/encoding/json/stream.ts"; * * const file = await Deno.open("./tmp.jsonl", { create: true, write: true }); * * readableStreamFromIterable([{ foo: "bar" }, { baz: 100 }]) *   .pipeThrough(new JsonStringifyStream()) *   .pipeThrough(new TextEncoderStream()) *   .pipeTo(file.writable) *   .then(() => console.log("write success")); * ``` */export class JsonStringifyStream extends TransformStream<unknown, string> {  /**   * @param options   * @param options.prefix Prefix to be added after stringify. The default is "".   * @param options.suffix Suffix to be added after stringify. The default is "\n".   * @param options.writableStrategy Controls the buffer of the TransformStream used internally. Check https://developer.mozilla.org/en-US/docs/Web/API/TransformStream/TransformStream.   * @param options.readableStrategy Controls the buffer of the TransformStream used internally. Check https://developer.mozilla.org/en-US/docs/Web/API/TransformStream/TransformStream.   */  constructor({    prefix = "",    suffix = "\n",    writableStrategy,    readableStrategy,  }: StringifyStreamOptions = {}) {    super(      {        transform(chunk, controller) {          controller.enqueue(`${prefix}${JSON.stringify(chunk)}${suffix}`);        },      },      writableStrategy,      readableStrategy,    );  }}