public class | source

Stream

You can directly use an instance of this class. streamUtils

This Stream class provide wrapper functions for readable-stream

Example:

import { stream } from 'causal-net.utils';

let reader = stream.makeReadable();
    
const TranformFn = (chunkData, chunkEncoding, afterTransformFn) =>{
    chunkData.x = (chunkData.x+1.5);
    let event = null;
    afterTransformFn(event, chunkData);
};
let transformer = stream.makeTransform(TranformFn);
    
const WriteFn = (chunkData, chunkEncoding, callback) =>{
    console.log({chunkData});
    callback();
};
let writer = stream.makeWritable(WriteFn);
    
reader.pipe(transformer).pipe(writer);
//write random int for every 100 ms    
setInterval(() => {
    reader.push({ x: Math.random() });
}, 100);

Test:

Stream readable must define

Constructor Summary

Public Constructor
public	constructor()

Member Summary

Private Members
private	stream: *

Method Summary

Public Methods
public	makeDuplex(writeFn: Function , readFn: Function ): Duplex create duplex object from writeFn and optional readFn.
public	makePipeline(streams: Array , onDataFn: Function ): Promise create pipeline from array of [readable, ...tranforms, writable].
public	makeReadable(readFn: Function ): Readable create reable object from readFn.
public	makeTransform(transformFn: Function ): Transform create transform object from transformFn
public	makeWritable(writeFn: Function ): Writable create writeable object from writeFn.

Public Constructors

public constructor() source

Private Members

private stream: * source

Public Methods

public makeDuplex(writeFn: Function , readFn: Function ): Duplex source

create duplex object from writeFn and optional readFn.

Params:

Name	Type	Attribute	Description
writeFn	Function		called function for new data
readFn	Function	optional default: null

Return:

Duplex

public makePipeline(streams: Array , onDataFn: Function ): Promise source

create pipeline from array of [readable, ...tranforms, writable]. This stream.makePipeline([readable, transform, writable]) equivalent to readable.pipe(transform).pipe(writable).

Params:

Name	Type	Attribute	Description
streams	Array		array of [readable, ...tranforms, writable]
onDataFn	Function	optional default: null	handle function for data event at readable

Return:

Promise

promise - resolve "Success" after finish or "Pipeline failed. ${err}".

public makeReadable(readFn: Function ): Readable source

create reable object from readFn.

Params:

Name	Type	Attribute	Description
readFn	Function		called function for new data

Return:

Readable

public makeTransform(transformFn: Function ): Transform source

create transform object from transformFn

Params:

Name	Type	Attribute	Description
transformFn	Function		called function for new data

Return:

Transform

public makeWritable(writeFn: Function ): Writable source

create writeable object from writeFn.

Params:

Name	Type	Attribute	Description
writeFn	Function		called function for new data

Return:

Writable