Unminified JavaScript

Detects unminified JavaScript that could be optimized

Rule ID	perf/unminified-js
Category	Performance
Scope	Per-page
Severity	warning
Weight	5/10

What it detects

Unminified JavaScript, based on newline ratio, comment volume, identifier length, indentation, and whitespace. Preserved /*! ... */ and //! license banners (the standard “keep on minify” convention used by Terser, esbuild, Vite, and Webpack) are stripped before analysis, so a fully minified bundle that legitimately retains license comments is not flagged.

Solution

Minify JavaScript to reduce file size and improve load times. Use build tools like Terser, esbuild, or UglifyJS. Most bundlers (Webpack, Vite, Rollup) minify automatically in production. Minification shortens variable names, removes whitespace, and dead code.

Options

This rule supports the following configuration options:

Option	Type	Default	Description
min_size_bytes	unknown	undefined	Minimum JS size in bytes to check for minification

Configuration Example

[rules."perf/unminified-js"]
min_size_bytes = undefined

Enable / Disable

Disable this rule

[rules]
disable = ["perf/unminified-js"]

Disable all Performance rules

[rules]
disable = ["perf/*"]

Enable only this rule

[rules]
enable = ["perf/unminified-js"]
disable = ["*"]