汇总常用的js对象Object的深比较方法

纯洁的代码
763 阅读6分钟

前言

这篇文章简单总结常用的深度比较方法，这些方法在react中用的特别多，特别是生命周期里面prop对比。因此，react和immutable天生结合性比较好。假设你项目中没有用immutable这种第三方库，那么实现深度比较的方法，在这里总结一下！

方法一

[JavaScript]
纯文本查看
复制代码
001
002
003
004
005
006
007
008
009
010
011
012
013
014
015
016
017
018
019
020
021
022
023
024
025
026
027
028
029
030
031
032
033
034
035
036
037
038
039
040
041
042
043
044
045
046
047
048
049
050
051
052
053
054
055
056
057
058
059
060
061
062
063
064
065
066
067
068
069
070
071
072
073
074
075
076
077
078
079
080
081
082
083
084
085
086
087
088
089
090
091
092
093
094
095
096
097
098
099
100
101
102
103
104
105
106
107
108
109
function equalsObject (obj1,obj) {
var p;
if (obj1 === obj) {
return true;
}
// some checks for native types first
// function and sring
if (typeof(obj1) === "function" || typeof(obj1) === "string" || obj1 instanceof String) {
return obj1.toString() === obj.toString();
}
// number
if (obj1 instanceof Number || typeof(obj1) === "number") {
if (obj instanceof Number || typeof(obj) === "number") {
return obj1.valueOf() === obj.valueOf();
}
return false;
}
// equalsObject(null,null) and equalsObject(undefined,undefined) do not inherit from the
// Object.prototype so we can return false when they are passed as obj
if (typeof(obj1) !== 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(obj1) === "object") {
if (Array.isArray(obj1)) { // check on arrays
return JSON.stringify(obj1) === JSON.stringify(obj);
} else { // anyway objects
for (p in obj1) {
if (typeof(obj1[p]) !== typeof(obj[p])) {
return false;
}
if ((obj1[p] === null) !== (obj[p] === null)) {
return false;
}
switch (typeof(obj1[p])) {
case 'undefined':
if (typeof(obj[p]) !== 'undefined') {
return false;
}
break;
case 'object':
if (obj1[p] !== null
&& obj[p] !== null
&& (obj1[p].constructor.toString() !== obj[p].constructor.toString()
|| !equalsObject(obj1[p],obj[p]))) {
return false;
}
break;
case 'function':
if (obj1[p].toString() !== obj[p].toString()) {
return false;
}
break;
default:
if (obj1[p] !== obj[p]) {
return false;
}
}
};
}
}
// at least check them with JSON
return JSON.stringify(sort(obj1)) === JSON.stringify(sort(obj));
}
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};
equalsObject(a,b) //true
equalsObject(f,g)//true
equalsObject(f,h)//false


方法二

[JavaScript]
纯文本查看
复制代码
001
002
003
004
005
006
007
008
009
010
011
012
013
014
015
016
017
018
019
020
021
022
023
024
025
026
027
028
029
030
031
032
033
034
035
036
037
038
039
040
041
042
043
044
045
046
047
048
049
050
051
052
053
054
055
056
057
058
059
060
061
062
063
064
065
066
067
068
069
070
071
072
073
074
075
076
077
078
079
080
081
082
083
084
085
086
087
088
089
090
091
092
093
094
095
096
097
098
099
100
101
102
103
104
105
106
107
108
109
110
111
112
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;
}


方法三

[JavaScript]
纯文本查看
复制代码
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
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;
}
}


方法四

[JavaScript]
纯文本查看
复制代码
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
const hasOwnProperty = (obj1: any, obj2: any) => {
switch (typeOf(obj1)) {
case "object":
return Object.prototype.hasOwnProperty.call(obj1, obj2);
case "array":
return typeOf(obj2) === "number" && obj2 >= 0 && obj1.length > obj2 ;
default:
return false;
}
};
const typeOf = (value) => Object.prototype.toString.call(value).replace(/\[|\]/gi, "").split(" ")[1].toLowerCase();
const length = (object) => {
switch (typeOf(object)) {
case "array":
return object.length;
case "object":
return Object.keys(object).length;
default:
return 0;
}
};
const every = (obj, func) => typeOf(obj) === "array" ? obj.every(func) : Object.entries(obj).every(([key, value]: [any, any]) => func(value, key));
const equal = (obj1, obj2) => {
switch (true) {
case typeOf(obj1) === "function" && typeOf(obj2) === "function":
return true;
case obj1 === obj2:
return true;
case typeOf(obj1) === typeOf(obj2) && ["object", "array"].includes(typeOf(obj1)) && length(obj1) === length(obj2):
return every(obj1, (value, key) => hasOwnProperty(obj2, key) && equal(value, obj2[key]));
default:
return false;
}
};


本文转自：https://www.haorooms.com/post/js_deepcompare


avatar
文章
阅读
粉丝