core-js/modules/es.promise.catch.js

'use strict';
var $ = require('../internals/export');
var IS_PURE = require('../internals/is-pure');
var FORCED_PROMISE_CONSTRUCTOR = require('../internals/promise-constructor-detection').CONSTRUCTOR;
var NativePromiseConstructor = require('../internals/promise-native-constructor');
var getBuiltIn = require('../internals/get-built-in');
var isCallable = require('../internals/is-callable');
var defineBuiltIn = require('../internals/define-built-in');

var NativePromisePrototype = NativePromiseConstructor && NativePromiseConstructor.prototype;

// `Promise.prototype.catch` method
// https://tc39.es/ecma262/#sec-promise.prototype.catch
$({ target: 'Promise', proto: true, forced: FORCED_PROMISE_CONSTRUCTOR, real: true }, {
  'catch': function (onRejected) {
    return this.then(undefined, onRejected);
  }
});

// makes sure that native promise-based APIs `Promise#catch` properly works with patched `Promise#then`
if (!IS_PURE && isCallable(NativePromiseConstructor)) {
  var method = getBuiltIn('Promise').prototype['catch'];
  if (NativePromisePrototype['catch'] !== method) {
    defineBuiltIn(NativePromisePrototype, 'catch', method, { unsafe: true });
  }
}