babel-plugin-transform-undefined-to-void

Some JavaScript implementations allow undefined to be overwritten, this may lead to peculiar bugs that are extremely hard to track down.

This plugin transforms undefined into void 0 which returns undefined regardless of if it's been reassigned.

Example

In

foo === undefined;

Out

foo === void 0;

npm install babel-plugin-transform-undefined-to-void --save-dev

.babelrc

{
  "plugins": ["transform-undefined-to-void"]
}

babel --plugins transform-undefined-to-void script.js

require("@babel/core").transform("code", {
  plugins: ["transform-undefined-to-void"]
});