@babel/plugin-transform-instanceof

示例

输入

JavaScript

foo instanceof Bar;

输出

JavaScript

function _instanceof(left, right) {
  if (
    right != null &&
    typeof Symbol !== "undefined" &&
    right[Symbol.hasInstance]
  ) {
    return right[Symbol.hasInstance](left);
  } else {
    return left instanceof right;
  }
}

_instanceof(foo, Bar);

安装

npm

npm install --save-dev @babel/plugin-transform-instanceof

Yarn

yarn add --dev @babel/plugin-transform-instanceof

pnpm

pnpm add --save-dev @babel/plugin-transform-instanceof

用法

使用配置文件（推荐）

babel.config.json

{
  "plugins": ["@babel/plugin-transform-instanceof"]
}

通过 CLI

Shell

babel --plugins @babel/plugin-transform-instanceof script.js

通过 Node API

JavaScript

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

参考

• ES6 规范：InstanceOf 运算符语义
• MDN：Symbol.hasInstance