Question 1

How to use UglifyJS with Webpack?

Accepted Answer

Integrate UglifyJS as a minimizer plugin in Webpack's optimization configuration; pass options via the Terser plugin (which forks UglifyJS) for better ES6+ support and performance.

Question 2

UglifyJS vs Terser which is better?

Accepted Answer

Terser is a more active fork of UglifyJS with faster updates for modern JavaScript, while UglifyJS is stable but may lag on newer features. Terser often offers better compression and speed for ES6+ codebases.

Question 3

How to keep function names in UglifyJS?

Accepted Answer

Use the --keep-fnames CLI flag or set keep_fnames: true in the API options; this preserves Function.prototype.name, which is useful for debugging or code that relies on it.

Question 4

Does UglifyJS support ES6 modules?

Accepted Answer

Yes, but for exotic ECMAScript features, the README recommends preprocessing with Babel first. Enable the --module flag to handle ES6 modules properly in compression.

Question 5

Why does UglifyJS break my code after minifying?

Accepted Answer

Common causes include property mangling altering dynamic property accesses or compiler assumptions not matching your code's behavior; disable --mangle-props or use reserved lists to mitigate.

Question 6

How to generate source maps with UglifyJS CLI?

Accepted Answer

Use --source-map with options like root and url; for example, --source-map "root='http://example.com/src',url='output.js.map'" to create a map file linked to the minified output.

Uglify

What is Uglify?

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