wishthis/node_modules/lead/index.js
2022-01-21 09:28:41 +01:00

61 lines
1.2 KiB
JavaScript

'use strict';
var Writable = require('flush-write-stream');
function listenerCount(stream, evt) {
return stream.listeners(evt).length;
}
function hasListeners(stream) {
return !!(listenerCount(stream, 'readable') || listenerCount(stream, 'data'));
}
function sinker(file, enc, callback) {
callback();
}
function sink(stream) {
var sinkAdded = false;
var sinkOptions = {
objectMode: stream._readableState.objectMode,
};
var sinkStream = new Writable(sinkOptions, sinker);
function addSink() {
if (sinkAdded) {
return;
}
if (hasListeners(stream)) {
return;
}
sinkAdded = true;
stream.pipe(sinkStream);
}
function removeSink(evt) {
if (evt !== 'readable' && evt !== 'data') {
return;
}
if (hasListeners(stream)) {
sinkAdded = false;
stream.unpipe(sinkStream);
}
}
stream.on('newListener', removeSink);
stream.on('removeListener', removeSink);
stream.on('removeListener', addSink);
// Sink the stream to start flowing
// Do this on nextTick, it will flow at slowest speed of piped streams
process.nextTick(addSink);
return stream;
}
module.exports = sink;