chunk-rate-readable

Measures the rate at which a given stream emits data chunks and streams the result.

var chunkRate = require('chunk-rate-readable')
  , numbers = require('../test/fixtures/number-readable');

var numbersStream = numbers({ to: 30, throttle: 200 })

var last = 0;
chunkRate(numbersStream, { objectMode: true })
  .on('data',  function (rate) {
    var indicator = rate === last 
      ? '='
      : rate > last ? '▲' : '▼';
    console.log('%d -> %s', rate, indicator);
    last = rate;
  });

Installation

npm install chunk-rate-readable

API

###function ChunkRateReadable (stream[, opts])

Creates a readable stream that will emit how many chunks the given stream emitted during the given interval.

@name ChunkRateReadable @function params:

• stream ReadableStream whose chunk rate is measured
• opts Object with the following properties:
  • objectMode {Boolean} if true rate is emitted as actual numbers, otherwise as buffers
  • interval {Number} at which to measure the rate (default: rate/500ms)

returns:

ReadableStream that will emit updates about the chunk rate of the given stream.

###chunkRateReadable.endSoon

Call this in case you want to tell the rate stream to end. Useful for testing and/or when you want to end your debugging session and allow the program to exit.

Similar Modules

• speed-meter measures the number of emitted bytes (vs. number of chunks) over a given time period

License

MIT