batchjs
Version:
Batch processing framework for NodeJS
58 lines (57 loc) • 1.89 kB
JavaScript
import { DiscardingSingleObjectDuplex } from "../interfaces/_index";
/**
* @class
* Class that allows you to validate that all elements in a stream match a given condition.
* @extends DiscardingSingleObjectDuplex
* @template T
* @example
* ```typescript
* const stream:AnyMatchStream<string> = new AnyMatchStream({
* objectMode: true,
* matcher: (chunk: string) => chunk.length > 2
* });
*
* stream.write("1"); // not match
* stream.write("2"); // not match
* stream.write("third"); // match
* stream.end();
*
* stream.on("data", (chunk: boolean) => {
* console.log(``Result: ${chunk}```);
* });
* ```
* ```shell
* >> Result: false
* ```
*/
export class AnyMatchStream extends DiscardingSingleObjectDuplex {
_matcher;
/**
* @constructor
* @param {AnyMatchStreamOptions} options - The options for the AnyMatchStream.
* @param [options.matcher] {Function} - The function that will be used to validate the chunk.
*/
constructor(options) {
super(options, () => this.result === false);
this._matcher = options.matcher;
}
/**
* A method to write data to the stream, filter the chunk and push it to the buffer or discard it, 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) {
const matcherResult = this._matcher(chunk);
if (this.result === undefined || this.result) {
this.result = !matcherResult;
this._flush();
}
if (matcherResult) {
this.emit("discard", chunk);
}
callback();
}
}