Nuke Pluto and Mars

    babel-plugin-annotate-pure-calls

    0.4.0 • Public • Published

    babel-plugin-annotate-pure-calls

    npm version Build Status npm

    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 the caution is advised. Target audience 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.

    Pure calls

    // pure call
    var inc = add(1)
     
    // clearly impure - no assignment context
    mutate({ prop: 'value' })

    Top level calls

    Top level call (in terms of this plugin) is one that gets executed during script initialization. So it is every call located at the root of a file, but also a call in an IIFE that gets executed at startup (including nested ones).

    var a = topLevelCall()
     
    b = function() {
      noTopLevelCall()
    }
     
    topLevelIIFEs = (function() {
      var c = (function() {
        var d = (function() {
          var e = topLevelCall()
        })()
      })()
    })()

    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('var inc = add(1)', {
      plugins: ['annotate-pure-calls'],
    })

    Usage with babel@6

    The plugin works with babel@6, you might see unmet peer dependency warning though. If you want to get rid of it, please install @babel/core@6.0.0-bridge.1.

    Similar projects

    Install

    npm i babel-plugin-annotate-pure-calls

    DownloadsWeekly Downloads

    70,172

    Version

    0.4.0

    License

    MIT

    Unpacked Size

    6.37 kB

    Total Files

    3

    Last publish

    Collaborators

    • andarist