Babel

The build will fail under any of the following conditions:

• Node.js is not installed
• The @babel/core package is not installed
• The @babel/cli package is not installed
• The @babel/preset-env package is not installed

JS

function greet(input) {
  console.log(input ?? "Hello, World!");
}
greet();

JS after Babel

"use strict";

function greet(input) {
  console.log(input !== null && input !== void 0 ? input : "Hello, World!");
}
greet();