@25sprout/react-starter/template/src/util/shallowEqual.js

25sprout web starter with React

/**
 * This is Copy from https://github.com/facebook/react/blob/master/packages/shared/shallowEqual.js
 *
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

/**
 * inlined Object.is polyfill to avoid requiring consumers ship their own
 * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/is
 */
function is(x, y) {
	if (x === y) {
		return x !== 0 || 1 / x === 1 / y;
	}

	return x !== x && y !== y; // eslint-disable-line no-self-compare
}

const { hasOwnProperty } = Object.prototype;

/**
 * Performs equality by iterating through keys on an object and returning false
 * when any key has values which are not strictly equal between the arguments.
 * Returns true when the values of all keys are strictly equal.
 */
function shallowEqual(objA, objB) {
	if (is(objA, objB)) {
		return true;
	}

	if (typeof objA !== 'object' || objA === null || typeof objB !== 'object' || objB === null) {
		return false;
	}

	const keysA = Object.keys(objA);
	const keysB = Object.keys(objB);

	if (keysA.length !== keysB.length) {
		return false;
	}

	// Test for A's keys different from B.
	for (let i = 0; i < keysA.length; i += 1) {
		if (!hasOwnProperty.call(objB, keysA[i]) || !is(objA[keysA[i]], objB[keysA[i]])) {
			return false;
		}
	}

	return true;
}

export default shallowEqual;