node package manager


gulp-bytediff Build Status NPM version Dependency Status

Compare file sizes before and after your gulp build process.


With npm do:

npm install gulp-bytediff --save-dev


Take any gulpplugin, or series of gulpplugins and see how much the build process added to, or removed from, your filesize. This example uses another of my modules, gulp-cssnano.

var gulp = require('gulp');
var bytediff = require('gulp-bytediff');
var csso = require('gulp-cssnano');
gulp.task('default', function() {


bytediff.start() or bytediff()

Creates a new property on the file object that saves its current size.


Outputs the difference between the property saved with the start() method and the current filesize.

Customise the output of this by using the format function. An example:

    // ... 
    .pipe(bytediff.stop(function(data) {
        var difference = (data.savings > 0) ? ' smaller.' : ' larger.';
        return data.fileName + ' is ' + data.percent + '%' + difference;

The function gets passed an object with the following properties:

  • fileName
  • startSize
  • endSize
  • savings
  • percent


Pull requests are welcome. If you add functionality, then please add unit tests to cover it.


MIT © Ben Briggs