Display files size difference between before and after point of pipeline stream. Designed for measuring efficiency minifying tools like uglify or cssnano.

This package was created for my other project disco-gulp look here for full examples. Based on gulp-sizediff but provides more flexible output, and some refactoring to modern JS

Install

$ npm install --save-dev gulp-size-difference

Usage

import sizeDifference from 'gulp-size-difference';

gulp.src(currentPaths.development.js + "**/*.js")
  .pipe(plumber({
    errorHandler: errorHandler
  }))
  .pipe(sizeDifference.start())
  .pipe(uglify())
  .pipe(sizeDifference.stop({title: `JS ${group}`}))
  .pipe(rename({"suffix": ".min"}))
  .pipe(gulp.dest(currentPaths.production.js))
  .on("end", _ => {
    callback();
   });

Standard output

[00:00:00] Starting 'post-js'...
[00:00:00] JS example1.js (saved 116 B - 39%)
[00:00:00] JS example2.js (saved 0 B - 0%)
[00:00:00] Finished 'post-js' after 72 ms

[00:00:00] Starting 'post-js'...
[00:00:00] JS all files (saved 4.83 kB - 41.8%)
[00:00:00] Finished 'post-js' after 74 ms

sizeDifference.start() or sizeDiff()

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

sizeDifference.stop(options)

Counts and outputs the difference between saved size and the current filesize.

options

title

Type: string
Default: ''

Give it a title so it's possible to distinguish the output of multiple instances logging at once.

allFiles

Type: boolean
Default: false

Run formatData for every file instead of just the total size diff.

customFormat

Type: function
Default: 'formatData()'

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

const formatDiff = (title = '', file = '', data = {}, isFile = false) => {
    title = title ? chalk.cyan(title) : title;
    file = file ? ' ' + chalk.green(file) : file;

    let message = `${title}${file}`;

    if (isFile) {
        message += chalk.white(` ~ saved ${prettyBytes(data.diffBytes)} (${Math.round(data.diffPercent * 100)}%)`);
    } else {
        const stats = [
            `Files count: ${data.filesCount}`,
            `Initial size: ${prettyBytes(data.initialSize)}`,
            `Final size: ${prettyBytes(data.finalSize)}`,
            `Difference bytes: ${prettyBytes(data.diffBytes)}`,
            `Difference percent: ${Math.round(data.diffPercent * 100)}%`,
            `Compression ratio: ${data.compressionRatio.toFixed(2)}`
        ];
        stats.forEach(filePath => {
            message += chalk.white(`\n\r${filePath}`);
        });
    }

    log(message);
}

import sizeDifference from 'gulp-size-difference';

gulp.src(currentPaths.development.js + "**/*.js")
    .pipe(plumber({
        errorHandler: errorHandler
    }))
    .pipe(sizeDifference.start())
    .pipe(uglify())
    .pipe(sizeDifference.stop({title: `JS ${group}`, customFormat: formatDiff}))
    .pipe(rename({"suffix": ".min"}))
    .pipe(gulp.dest(currentPaths.production.js))
    .on("end", _ => {
        callback();
    });

[00:00:00] Starting 'post-js'...
[00:00:00] JS example1.js ~ saved 116 B (39%)
[00:00:00] JS example2.js ~ saved 0 B (0%)
[00:00:00] Finished 'post-js' after 72 ms

[00:00:00] Starting 'post-js'...
[00:00:00] JS all files
Files count: 2
Initial size: 190 B
Final size: 74 B
Difference bytes: 116 B
Difference percent: 39%
Compression ratio: 0.61
[00:00:00] Finished 'post-js' after 74 ms

title

Type: string

String given with sizeDiff.stop()

file

Type: string

String relative path to file or all files text.

data

Type: Object

Difference data object

• Files count: data.filesCount
• Initial size: data.initialSize
• Final size: data.finalSize
• Difference bytes: data.diffBytes
• Pretty initial size: data.prettyInitialSize
• Pretty final size: data.prettyFinalSize
• Pretty difference bytes: data.prettyDiffBytes
• Difference percent: data.diffPercent
• Compression ratio: data.compressionRatio

options

Type: Object

Passed options object for detecting output mode.