babel-plugin-annotate-pure-calls

babel-plugin-annotate-pure-calls

This plugins helps with automatic #PURE annotation insertion. It add the comment to top level call expressions and new expressions in assignment contexts (those are considered by the plugin as side effect free). This helps UglifyJS to perform dead code elimination more efficiently and therefore reduces the bundle sizes for the consumers.

NOTE It might break your code, so use on your own risk. Target audiance for the plugin are libraries, which in vast major of use cases do not introduce side effects in top level calls. That doesn't mean that application bundles cannot benefit from the plugin.

Installation

npm install --save-dev babel-plugin-annotate-pure-calls

Usage

Via .babelrc (Recommended)

.babelrc

{
  "plugins": ["annotate-pure-calls"]
}

Via CLI

babel --plugins annotate-pure-calls script.js

Via Node API

require("babel-core").transform("code", {
  plugins: ["annotate-pure-calls"]
});