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@babel/plugin-transform-instanceof

NOTE: This plugin is included in @babel/preset-env

Example​

In

JavaScript
foo instanceof Bar;

Out

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);

Installation​

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

Usage​

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

Via CLI​

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

Via Node API​

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

References​