stream3-concat

Dead simple stream concatenator for node stream 3 API

Installation

``shellscript
npm install --save stream3-concat
`

Usage

$3


`javascript
const Concat = require('stream3-concat')

// Concatenates N streams
const myConcat = new Concat([stream1, stream2, ...])

// Just pass through 1 single stream
const myConcat = new Concat(stream1)

// Start with an empty stream
const myConcat = new Concat()

// Call function as a factory also works!
const myConcat = Concat()
`

$3


`javascript
myConcat = new Concat()
myConcat.add(stream1)
myConcat.add(stream2)
`

$3


`javascript
myConcat = new Concat([stream1, stream2])
//...
myConcat.remove(stream1)
`

Notice: this method might trigger the end event on the stream if the stream being removed is the last one.

$3


`javascript
myConcat = new Concat([stream1, stream2])
//...
myConcat.clear()
`

Notice: this method will trigger the end event on the stream.

$3


`javascript
myConcat = new Concat([stream1, stream2])
//...
myConcat.close()
`

Notice: this method will trigger the end and the close events on the concat stream. Once a stream is closed, it can't be used anymore.

If true is passed as the first parameter, any of the underlying streams that has a close() method will be closed as well.

`javascript
myConcat = new Concat([stream1, stream2])
//...
myConcat.close(true)
`

$3


`javascript
myConcat.add(stream1)
.add(stream2)
.add(stream3)
.remove(stream2)
.clear()
.add(stream3)
`

$3

stream3-concat is a Transform stream and therefore it can emit any events its base class can.

Important Notes

$3

If you try to concatenate synchronous streams, they will run in series, that is, one stream will only start to send data after the other finishes.

For example:

`javascript
const Readable = require('stream').Readable

const stream1 = new Readable({
objectMode: true,
highWaterMark: 1,
read: function () {
this.push({
'a' : Math.random()
})
}
})

const stream2 = new Readable({
objectMode: true,
highWaterMark: 1,
read: function () {
this.push({
'b' : 1
})
}
})


const concat = new Concat([stream1, stream2])
concat.on('data', function (data) {
console.log(data)
})
`

In the code above, stream2 data will never be read, since both stream are infinite and synchronous. If you want to run two streams in parallel, you should defer them:

`javascript
const Readable = require('stream').Readable

const stream1 = new Readable({
objectMode: true,
highWaterMark: 1,
read: function () {
setImmediate(() => {
this.push({
'a' : Math.random()
})
})
}
})

const stream2 = new Readable({
objectMode: true,
highWaterMark: 1,
read: function () {
setImmediate(() => {
this.push({
'b' : 1
})
})
}
})


const concat = new Concat([stream1, stream2])
concat.on('data', function (data) {
console.log(data)
})
``