@babel/core

babel 核心代码（编译es6）

Babel is a compiler for writing next generation JavaScript.

Babel is a tool that helps you write code in the latest version of JavaScript. When your supported environments don’t support certain features natively, Babel will help you compile those features down to a supported version.

https://github.com/babel/babel

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// ES2020 nullish coalescing
function greet(input) {
  return input ?? "Hello world";
}

会编译成

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function greet(input) {
  return input != null ? input : "Hello world";
}

​