jiff/lib/deepEquals.js

JSON diff and patch based on rfc6902

module.exports = deepEquals;

/**
 * Compare 2 JSON values, or recursively compare 2 JSON objects or arrays
 * @param {object|array|string|number|boolean|null} a
 * @param {object|array|string|number|boolean|null} b
 * @returns {boolean} true iff a and b are recursively equal
 */
function deepEquals(a, b) {
	if(a === b) {
		return true;
	}

	if(Array.isArray(a) && Array.isArray(b)) {
		return compareArrays(a, b);
	}

	if(typeof a === 'object' && typeof b === 'object') {
		return compareObjects(a, b);
	}

	return false;
}

function compareArrays(a, b) {
	if(a.length !== b.length) {
		return false;
	}

	for(var i = 0; i<a.length; ++i) {
		if(!deepEquals(a[i], b[i])) {
			return false;
		}
	}

	return true;
}

function compareObjects(a, b) {
	if((a === null && b !== null) || (a !== null && b === null)) {
		return false;
	}

	var akeys = Object.keys(a);
	var bkeys = Object.keys(b);

	if(akeys.length !== bkeys.length) {
		return false;
	}

	for(var i = 0, k; i<akeys.length; ++i) {
		k = akeys[i];
		if(!(k in b && deepEquals(a[k], b[k]))) {
			return false;
		}
	}

	return true;
}