batchjs/dist/esm/streams/classes/HasElementsStream.js

Batch processing framework for NodeJS

import { SingleObjectDuplex } from "../interfaces/_index";
/**
 * @class
 * Class that allows you to validate that a stream has elements.
 * @extends SingleObjectDuplex
 * @template T
 * @example
 * ```typescript
 * const stream:HasElementsStream<string> = new HasElementsStream({
 *     objectMode: true,
 * });
 *
 * stream.write("first"); // not empty
 * stream.end();
 *
 * stream.on("data", (chunk: boolean) => {
 *     console.log(``Result: ${chunk}```);
 * });
 * ```
 * ```shell
 * >> Result: false
 * ```
 */
export class HasElementsStream extends SingleObjectDuplex {
    result = false;
    /**
     * @constructor
     * @param {ObjectDuplexOptions} options - The options for the HasElementsStream.
     */
    constructor(options) {
        super(options, () => this.result);
    }
    /**
     * A method to write data to the stream, setting the hasChunks flag to true, and execute the callback.
     *
     * @param {T} chunk - The data chunk to write to the stream.
     * @param {BufferEncoding} encoding - The encoding of the data.
     * @param {TransformCallback} callback - The callback function to be executed after writing the data.
     * @return {void} This function does not return anything.
     */
    _write(chunk, encoding, callback) {
        this.result = true;
        this._flush();
        callback();
    }
}