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@babel/plugin-transform-duplicate-keys

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

This plugin actually converts duplicate keys in objects to be computed properties, which then must be handled by the @babel/plugin-transform-computed-properties plugin. The final result won't contain any object literals with duplicate keys.

Example​

In

JavaScript
var x = { a: 5, a: 6 };
var y = {
  get a() {},
  set a(x) {},
  a: 3,
};

Out

JavaScript
var x = { a: 5, ["a"]: 6 };
var y = {
  get a() {},
  set a(x) {},
  ["a"]: 3,
};

Installation​

npm install --save-dev @babel/plugin-transform-duplicate-keys

Usage​

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

Via CLI​

Shell
babel --plugins @babel/plugin-transform-duplicate-keys script.js

Via Node API​

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