《javascript算法--对象的比较》

方法一:JSON.stringify()

此方法简单,适用于当两个对象的属性顺序相同的时候。
var user1 = {name : "nerd", org: "dev"};
var user2 = {name : "nerd", org: "dev"};
var eq = user1 == user2;
alert(eq); // gives false var eq1 = JSON.stringify(user1) == JSON.stringify(user2); alert(eq1); // gives true

方法二:深度比较两个对象

深度比较两个对象,当对象的属性类型相同且属性的值相同(对象的顺序可以不一样),两个对象就相等。
function deepCompare(x, y) {
var i, l, leftChain, rightChain; function compare2Objects(x, y) {
var p; // remember that NaN === NaN returns false
// and isNaN(undefined) returns true
if (isNaN(x) && isNaN(y) && typeof x === 'number' && typeof y === 'number') {
return true;
} // Compare primitives and functions.
// Check if both arguments link to the same object.
// Especially useful on the step where we compare prototypes
if (x === y) {
return true;
} // Works in case when functions are created in constructor.
// Comparing dates is a common scenario. Another built-ins?
// We can even handle functions passed across iframes
if ((typeof x === 'function' && typeof y === 'function') ||
(x instanceof Date && y instanceof Date) ||
(x instanceof RegExp && y instanceof RegExp) ||
(x instanceof String && y instanceof String) ||
(x instanceof Number && y instanceof Number)) {
return x.toString() === y.toString();
} // At last checking prototypes as good as we can
if (!(x instanceof Object && y instanceof Object)) {
return false;
} if (x.isPrototypeOf(y) || y.isPrototypeOf(x)) {
return false;
} if (x.constructor !== y.constructor) {
return false;
} if (x.prototype !== y.prototype) {
return false;
} // Check for infinitive linking loops
if (leftChain.indexOf(x) > -1 || rightChain.indexOf(y) > -1) {
return false;
} // Quick checking of one object being a subset of another.
// todo: cache the structure of arguments[0] for performance
for (p in y) {
if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
return false;
} else if (typeof y[p] !== typeof x[p]) {
return false;
}
} for (p in x) {
if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
return false;
} else if (typeof y[p] !== typeof x[p]) {
return false;
} switch (typeof(x[p])) {
case 'object':
case 'function': leftChain.push(x);
rightChain.push(y); if (!compare2Objects(x[p], y[p])) {
return false;
} leftChain.pop();
rightChain.pop();
break; default:
if (x[p] !== y[p]) {
return false;
}
break;
}
} return true;
} if (arguments.length < 1) {
return true; //Die silently? Don't know how to handle such case, please help...
// throw "Need two or more arguments to compare";
} for (i = 1, l = arguments.length; i < l; i++) { leftChain = []; //Todo: this can be cached
rightChain = []; if (!compare2Objects(arguments[0], arguments[i])) {
return false;
}
} return true;
}

参考资料:

1.http://*.com/questions/1068834/object-comparison-in-javascript
2.https://segmentfault.com/a/1190000008187911
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