@babel/plugin-check-constants

Validate ES2015 constants (prevents reassignment of const variables).

Example

In

const a = 1;
a = 2;

Out

repl: "a" is read-only
  1 | const a = 1;
> 2 | a = 2;
    | ^

Installation

npm install --save-dev @babel/plugin-check-constants

Usage

Via .babelrc (Recommended)

.babelrc

{
  "plugins": ["@babel/check-constants"]
}

Via CLI

babel --plugins @babel/check-constants script.js

Via Node API

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

Note

This check will only validate consts. If you need it to compile down to var then you must also install and enable @babel/plugin-transform-block-scoping.