Example

In

function foo() {var x = 1;}
function bar() { var x = f(); }
function baz() {
  var x = 1;
  console.log(x);
  function unused() {
    return 5;
  }
}

Out

function foo() {}
function bar() { f(); }
function baz() {
  console.log(1);
}

Installation

npm install babel-plugin-minify-dead-code-elimination --save-dev

Usage

With a configuration file (Recommended)

// without options
{
  "plugins": ["minify-dead-code-elimination"]
}

// with options
{
  "plugins": ["minify-dead-code-elimination", { "optimizeRawSize": true }]
}

Via CLI

babel --plugins minify-dead-code-elimination script.js

Via Node API

require("@babel/core").transform("code", {
  plugins: ["minify-dead-code-elimination"]
});

Options

• keepFnName - prevent plugin from removing function name. Useful for code depending on fn.name
• keepFnArgs - prevent plugin from removing function args. Useful for code depending on fn.length
• keepClassName - prevent plugin from removing class name. Useful for code depending on cls.name
• tdz - Account for TDZ (Temporal Dead Zone)

You can read more about configuring plugin options here