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babel-plugin-transform-remove-undefined

For functions, this removes return arguments that evaluate to undefined.

Example

In

JavaScript
let a = void 0;
function foo() {
var b = undefined;
return undefined;
}

Out

JavaScript
let a;
function foo() {
var b;
return;
}

Installation

npm install babel-plugin-transform-remove-undefined --save-dev

Usage

babel.config.json
{
"plugins": ["babel-plugin-transform-remove-undefined"]
}

Via CLI

Shell
babel --plugins babel-plugin-transform-remove-undefined script.js

Via Node API

JavaScript
require("@babel/core").transformSync("code", {
plugins: ["babel-plugin-transform-remove-undefined"],
});

Options

  • tdz - Detect usages before declaration/initialization in let/const(throws) and var(void 0)
tip

You can read more about configuring plugin options here