streamspeed

A simple way to keep track of the speed of your readable streams.

Usage

const StreamSpeed = require('streamspeed');

let rs = fs.createReadStream('somefile.avi');
let ss = new StreamSpeed();
ss.add(rs);

// Listen for events emitted by streamspeed on the given stream.
ss.on('speed', (speed) => {
  console.log('Reading at', speed, 'bytes per second');
});

Keep track of a group of streams

let group = new Streamspeed();
group.add(stream1);
group.add(stream2);
group.add(stream3);

group.on('speed', (speed) => {
  console.log('now reading at', speed, 'bps');
});

API

new StreamSpeed([options])

A group that can be used to watch several streams. Will emit speed events. options can have the following properties,

• timeUnit - Defaults to 1000 for speed per second. If you want another unit such as per hour, use 1000 * 60 * 60.
• range - The time in ms to use to calculate the speed over. Defaults to 1000. The longer this is, the longer it'll speed will ramp up and down until it stabilizes for a big readstream. The shorter it is, the more responsive it is to sudden speed changes.

StreamSpeed#add(stream)

Adds stream to group.

StreamSpeed#remove(stream)

Removes stream from group.

StreamSpeed#getSpeed()

Get current speed.

StreamSpeed#getStreamSpeed(stream)

Get an individual's stream's current speed.

StreamSpeed#getStreams()

Returns a list of all streams in the group.

StreamSpeed.toHuman(bytes, options)

Helper method to convert bytes to a human readable string.

StreamSpeed.toHuman(1500);                                  // 1.46KB
StreamSpeed.toHuman(1024 * 1024);                           // 1MB
StreamSpeed.toHuman(1024 * 1024 * 20.5, { timeUnit: 's' }); // 20.5MB/s
StreamSpeed.toHuman(1024 * 1024 * 20.5, { precision: 3 });  // 20.50MB

Event: 'speed'

• number - Speed at which streams in the group are being read.

Will be emitted every time a stream is read and only if there is a change in speed.

Install

npm install streamspeed

Tests

Tests are written with mocha

npm test