Fix Guide

How to Minify Your JavaScript

Compress JS by removing comments, whitespace and shortening names — often a 40-60% reduction.

Easy Medium Impact 10 min

Unminified JavaScript ships full variable names, comments and whitespace, so the browser downloads and parses far more than it needs to. Enable minification in your build, and serve the result with Brotli or gzip. On top of that, splitting the bundle so each page loads only its own code usually saves more than minification alone.

Why It Matters

Unminified JavaScript ships comments and long variable names the browser doesn't need, and JS is expensive to download and parse. Minification (and tree-shaking) cuts bytes and speeds up execution.

How to Fix

Build for production

Use your bundler's production build (esbuild, terser, SWC) so JS is minified and dead code removed.

Tree-shake and split

Import only what you use and code-split per route so each page ships less JS.

Code Fix

javascript

Before (broken)

function calculateTotal(price, quantity) {
  // multiply price by quantity
  return price * quantity;
}

After (fixed)

function calculateTotal(t,a){return t*a}

Platform-Specific Instructions

WordPress

Enable "Minify JavaScript" in your caching plugin; test for breakage since some plugin scripts dislike combining.

Next.js

Production builds minify + tree-shake automatically.

Check with our tool

JavaScript Minifier

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