How to Format Minified JavaScript

Minification is a standard production practice where spaces, line breaks, and comments are stripped away to reduce file size. While this is great for network performance, it makes debugging near impossible. Formatting minified JavaScript—often called "un-minifying"—restores structural readability.

The Challenge of Minified Code

Minifiers like Terser or UglifyJS don't just remove spaces; they often rename variables (mangling) and flatten conditional statements. A beautifier cannot reverse mangled variable names (e.g., changing a back to userData), but it can restore the visual hierarchy.

!function(e){var t={};function n(r){if(t[r])return t[r].exports;var o=t[r]={i:r,l:!1,exports:{}}}

!function(e) {
  var t = {};
  function n(r) {
    if (t[r]) return t[r].exports;
    var o = t[r] = {
      i: r,
      l: !1,
      exports: {}
    }
  }
}

How to Un-minify Safely

To safely un-minify code, paste the production payload into a dedicated JavaScript formatter. Ensure that you select a generous indentation (like 4 spaces) to easily track the deep nesting that minifiers often create when transforming if/else blocks into ternary operators.

Remember that debugging formatted minified code still requires effort due to single-letter variables, but seeing the block structure makes it possible to set accurate breakpoints in your browser's DevTools.