JavaScript 中的对象比较

var user1 = {name : "nerd", org: "dev"};
var user2 = {name : "nerd", org: "dev"};
var eq = user1 == user2;
alert(eq); // gives false
var eq = Object.toJSON(user1) == Object.toJSON(user2);
alert(eq); // gives true

答案

JSON.stringify(obj1) === JSON.stringify(obj2)
x = {a: 1, b: 2};
 y = {b: 2, a: 1};
function deepCompare () {
  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;
}
Object.equals = function( x, y ) {
  if ( x === y ) return true;
    // if both x and y are null or undefined and exactly the same

  if ( ! ( x instanceof Object ) || ! ( y instanceof Object ) ) return false;
    // if they are not strictly equal, they both need to be Objects

  if ( x.constructor !== y.constructor ) return false;
    // they must have the exact same prototype chain, the closest we can do is
    // test there constructor.

  for ( var p in x ) {
    if ( ! x.hasOwnProperty( p ) ) continue;
      // other properties were tested using x.constructor === y.constructor

    if ( ! y.hasOwnProperty( p ) ) return false;
      // allows to compare x[ p ] and y[ p ] when set to undefined

    if ( x[ p ] === y[ p ] ) continue;
      // if they have the same strict value or identity then they are equal

    if ( typeof( x[ p ] ) !== "object" ) return false;
      // Numbers, Strings, Functions, Booleans must be strictly equal

    if ( ! Object.equals( x[ p ],  y[ p ] ) ) return false;
      // Objects and Arrays must be tested recursively
  }

  for ( p in y ) {
    if ( y.hasOwnProperty( p ) && ! x.hasOwnProperty( p ) ) return false;
      // allows x[ p ] to be set to undefined
  }
  return true;
}
Utils.compareObjects = function(o1, o2){
    for(var p in o1){
        if(o1.hasOwnProperty(p)){
            if(o1[p] !== o2[p]){
                return false;
            }
        }
    }
    for(var p in o2){
        if(o2.hasOwnProperty(p)){
            if(o1[p] !== o2[p]){
                return false;
            }
        }
    }
    return true;
};
Object.prototype.equals = function(x)
{
    for(p in this)
    {
        switch(typeof(this[p]))
        {
            case 'object':
                if (!this[p].equals(x[p])) { return false }; break;
            case 'function':
                if (typeof(x[p])=='undefined' || (p != 'equals' && this[p].toString() != x[p].toString())) { return false; }; break;
            default:
                if (this[p] != x[p]) { return false; }
        }
    }

    for(p in x)
    {
        if(typeof(this[p])=='undefined') {return false;}
    }

    return true;
}
function unwrapStringOrNumber(obj) {
    return (obj instanceof Number || obj instanceof String 
            ? obj.valueOf() 
            : obj);
}
function areEquivalent(a, b) {
    a = unwrapStringOrNumber(a);
    b = unwrapStringOrNumber(b);
    if (a === b) return true; //e.g. a and b both null
    if (a === null || b === null || typeof (a) !== typeof (b)) return false;
    if (a instanceof Date) 
        return b instanceof Date && a.valueOf() === b.valueOf();
    if (typeof (a) !== "object") 
        return a == b; //for boolean, number, string, xml

    var newA = (a.areEquivalent_Eq_91_2_34 === undefined),
        newB = (b.areEquivalent_Eq_91_2_34 === undefined);
    try {
        if (newA) a.areEquivalent_Eq_91_2_34 = [];
        else if (a.areEquivalent_Eq_91_2_34.some(
            function (other) { return other === b; })) return true;
        if (newB) b.areEquivalent_Eq_91_2_34 = [];
        else if (b.areEquivalent_Eq_91_2_34.some(
            function (other) { return other === a; })) return true;
        a.areEquivalent_Eq_91_2_34.push(b);
        b.areEquivalent_Eq_91_2_34.push(a);

        var tmp = {};
        for (var prop in a) 
            if(prop != "areEquivalent_Eq_91_2_34") 
                tmp[prop] = null;
        for (var prop in b) 
            if (prop != "areEquivalent_Eq_91_2_34") 
                tmp[prop] = null;

        for (var prop in tmp) 
            if (!areEquivalent(a[prop], b[prop]))
                return false;
        return true;
    } finally {
        if (newA) delete a.areEquivalent_Eq_91_2_34;
        if (newB) delete b.areEquivalent_Eq_91_2_34;
    }
}
function countProps(obj) {
    var count = 0;
    for (k in obj) {
        if (obj.hasOwnProperty(k)) {
            count++;
        }
    }
    return count;
};

function objectEquals(v1, v2) {

    if (typeof(v1) !== typeof(v2)) {
        return false;
    }

    if (typeof(v1) === "function") {
        return v1.toString() === v2.toString();
    }

    if (v1 instanceof Object && v2 instanceof Object) {
        if (countProps(v1) !== countProps(v2)) {
            return false;
        }
        var r = true;
        for (k in v1) {
            r = objectEquals(v1[k], v2[k]);
            if (!r) {
                return false;
            }
        }
        return true;
    } else {
        return v1 === v2;
    }
}

assert.isTrue(objectEquals(null,null));
assert.isFalse(objectEquals(null,undefined));

assert.isTrue(objectEquals("hi","hi"));
assert.isTrue(objectEquals(5,5));
assert.isFalse(objectEquals(5,10));

assert.isTrue(objectEquals([],[]));
assert.isTrue(objectEquals([1,2],[1,2]));
assert.isFalse(objectEquals([1,2],[2,1]));
assert.isFalse(objectEquals([1,2],[1,2,3]));

assert.isTrue(objectEquals({},{}));
assert.isTrue(objectEquals({a:1,b:2},{a:1,b:2}));
assert.isTrue(objectEquals({a:1,b:2},{b:2,a:1}));
assert.isFalse(objectEquals({a:1,b:2},{a:1,b:3}));

assert.isTrue(objectEquals({1:{name:"mhc",age:28}, 2:{name:"arb",age:26}},{1:{name:"mhc",age:28}, 2:{name:"arb",age:26}}));
assert.isFalse(objectEquals({1:{name:"mhc",age:28}, 2:{name:"arb",age:26}},{1:{name:"mhc",age:28}, 2:{name:"arb",age:27}}));

assert.isTrue(objectEquals(function(x){return x;},function(x){return x;}));
assert.isFalse(objectEquals(function(x){return x;},function(y){return y+2;}));
Object.prototype.equals = function(x){
    for (var p in this) {
        if(typeof(this[p]) !== typeof(x[p])) return false;
        if((this[p]===null) !== (x[p]===null)) return false;
        switch (typeof(this[p])) {
            case 'undefined':
                if (typeof(x[p]) != 'undefined') return false;
                break;
            case 'object':
                if(this[p]!==null && x[p]!==null && (this[p].constructor.toString() !== x[p].constructor.toString() || !this[p].equals(x[p]))) return false;
                break;
            case 'function':
                if (p != 'equals' && this[p].toString() != x[p].toString()) return false;
                break;
            default:
                if (this[p] !== x[p]) return false;
        }
    }
    return true;
}
var a = {a: 'text', b:[0,1]};
var b = {a: 'text', b:[0,1]};
var c = {a: 'text', b: 0};
var d = {a: 'text', b: false};
var e = {a: 'text', b:[1,0]};
var f = {a: 'text', b:[1,0], f: function(){ this.f = this.b; }};
var g = {a: 'text', b:[1,0], f: function(){ this.f = this.b; }};
var h = {a: 'text', b:[1,0], f: function(){ this.a = this.b; }};
var i = {
    a: 'text',
    c: {
        b: [1, 0],
        f: function(){
            this.a = this.b;
        }
    }
};
var j = {
    a: 'text',
    c: {
        b: [1, 0],
        f: function(){
            this.a = this.b;
        }
    }
};
var k = {a: 'text', b: null};
var l = {a: 'text', b: undefined};

如果要显式检查方法,则可以使用 method.toSource()或 method.toString()方法。

Object.defineProperty(Object.prototype, "equals", {
    enumerable: false,
    value: function (obj) {
        var p;
        if (this === obj) {
            return true;
        }

        // some checks for native types first

        // function and sring
        if (typeof(this) === "function" || typeof(this) === "string" || this instanceof String) { 
            return this.toString() === obj.toString();
        }

        // number
        if (this instanceof Number || typeof(this) === "number") {
            if (obj instanceof Number || typeof(obj) === "number") {
                return this.valueOf() === obj.valueOf();
            }
            return false;
        }

        // null.equals(null) and undefined.equals(undefined) do not inherit from the 
        // Object.prototype so we can return false when they are passed as obj
        if (typeof(this) !== typeof(obj) || obj === null || typeof(obj) === "undefined") {
            return false;
        }

        function sort (o) {
            var result = {};

            if (typeof o !== "object") {
                return o;
            }

            Object.keys(o).sort().forEach(function (key) {
                result[key] = sort(o[key]);
            });

            return result;
        }

        if (typeof(this) === "object") {
            if (Array.isArray(this)) { // check on arrays
                return JSON.stringify(this) === JSON.stringify(obj);                
            } else { // anyway objects
                for (p in this) {
                    if (typeof(this[p]) !== typeof(obj[p])) {
                        return false;
                    }
                    if ((this[p] === null) !== (obj[p] === null)) {
                        return false;
                    }
                    switch (typeof(this[p])) {
                    case 'undefined':
                        if (typeof(obj[p]) !== 'undefined') {
                            return false;
                        }
                        break;
                    case 'object':
                        if (this[p] !== null 
                                && obj[p] !== null 
                                && (this[p].constructor.toString() !== obj[p].constructor.toString() 
                                        || !this[p].equals(obj[p]))) {
                            return false;
                        }
                        break;
                    case 'function':
                        if (this[p].toString() !== obj[p].toString()) {
                            return false;
                        }
                        break;
                    default:
                        if (this[p] !== obj[p]) {
                            return false;
                        }
                    }
                };

            }
        }

        // at least check them with JSON
        return JSON.stringify(sort(this)) === JSON.stringify(sort(obj));
    }
});
assertFalse({}.equals(null));
    assertFalse({}.equals(undefined));

    assertTrue("String", "hi".equals("hi"));
    assertTrue("Number", new Number(5).equals(5));
    assertFalse("Number", new Number(5).equals(10));
    assertFalse("Number+String", new Number(1).equals("1"));

    assertTrue([].equals([]));
    assertTrue([1,2].equals([1,2]));
    assertFalse([1,2].equals([2,1]));
    assertFalse([1,2].equals([1,2,3]));

    assertTrue(new Date("2011-03-31").equals(new Date("2011-03-31")));
    assertFalse(new Date("2011-03-31").equals(new Date("1970-01-01")));

    assertTrue({}.equals({}));
    assertTrue({a:1,b:2}.equals({a:1,b:2}));
    assertTrue({a:1,b:2}.equals({b:2,a:1}));
    assertFalse({a:1,b:2}.equals({a:1,b:3}));

    assertTrue({1:{name:"mhc",age:28}, 2:{name:"arb",age:26}}.equals({1:{name:"mhc",age:28}, 2:{name:"arb",age:26}}));
    assertFalse({1:{name:"mhc",age:28}, 2:{name:"arb",age:26}}.equals({1:{name:"mhc",age:28}, 2:{name:"arb",age:27}}));

    assertTrue("Function", (function(x){return x;}).equals(function(x){return x;}));
    assertFalse("Function", (function(x){return x;}).equals(function(y){return y+2;}));

    var a = {a: 'text', b:[0,1]};
    var b = {a: 'text', b:[0,1]};
    var c = {a: 'text', b: 0};
    var d = {a: 'text', b: false};
    var e = {a: 'text', b:[1,0]};
    var f = {a: 'text', b:[1,0], f: function(){ this.f = this.b; }};
    var g = {a: 'text', b:[1,0], f: function(){ this.f = this.b; }};
    var h = {a: 'text', b:[1,0], f: function(){ this.a = this.b; }};
    var i = {
        a: 'text',
        c: {
            b: [1, 0],
            f: function(){
                this.a = this.b;
            }
        }
    };
    var j = {
        a: 'text',
        c: {
            b: [1, 0],
            f: function(){
                this.a = this.b;
            }
        }
    };
    var k = {a: 'text', b: null};
    var l = {a: 'text', b: undefined};

    assertTrue(a.equals(b));
    assertFalse(a.equals(c));
    assertFalse(c.equals(d));
    assertFalse(a.equals(e));
    assertTrue(f.equals(g));
    assertFalse(h.equals(g));
    assertTrue(i.equals(j));
    assertFalse(d.equals(k));
    assertFalse(k.equals(l));
Object.prototype.equals = function(b) {
    var a = this;
    for(i in a) {
        if(typeof b[i] == 'undefined') {
            return false;
        }
        if(typeof b[i] == 'object') {
            if(!b[i].equals(a[i])) {
                return false;
            }
        }
        if(b[i] != a[i]) {
            return false;
        }
    }
    for(i in b) {
        if(typeof a[i] == 'undefined') {
            return false;
        }
        if(typeof a[i] == 'object') {
            if(!a[i].equals(b[i])) {
                return false;
            }
        }
        if(a[i] != b[i]) {
            return false;
        }
    }
    return true;
}

var a = {foo:'bar', bar: {blub:'bla'}};
var b = {foo:'bar', bar: {blub:'blob'}};
alert(a.equals(b)); // alert's a false