我需要能够在运行时合并两个(非常简单)JavaScript对象。例如,我想:
var obj1 = { food: 'pizza', car: 'ford' }
var obj2 = { animal: 'dog' }
obj1.merge(obj2);
//obj1 now has three properties: food, car, and animal
是否有一种内置的方法来实现这一点?我不需要递归,也不需要合并函数,只需要平面对象上的方法。
我需要能够在运行时合并两个(非常简单)JavaScript对象。例如,我想:
var obj1 = { food: 'pizza', car: 'ford' }
var obj2 = { animal: 'dog' }
obj1.merge(obj2);
//obj1 now has three properties: food, car, and animal
是否有一种内置的方法来实现这一点?我不需要递归,也不需要合并函数,只需要平面对象上的方法。
当前回答
使用object.assign和spread运算符合并两个对象。
错误的方式(修改原始对象,因为目标是o1)
var o1 = { X: 10 };
var o2 = { Y: 20 };
var o3 = { Z: 30 };
var merge = Object.assign(o1, o2, o3);
console.log(merge) // {X:10, Y:20, Z:30}
console.log(o1) // {X:10, Y:20, Z:30}
正确的方式
Object.assign({},o1,o2,o3)==>以新对象为目标{…o1,…o2,…o3}==>扩展对象
变量o1={X:10};var o2={Y:20};var o3={Z:30};console.log('不修改原始对象,因为目标{}');var merge=对象赋值({},o1,o2,o3);console.log(合并);//{X:10,Y:20,Z:30}控制台日志(o1)console.log('不修改原始对象')var spreadMerge={…o1,…o2,…o3};console.log(spreadMerge);控制台日志(o1);
其他回答
您可以简单地使用jQuery扩展
var obj1 = { val1: false, limit: 5, name: "foo" };
var obj2 = { val2: true, name: "bar" };
jQuery.extend(obj1, obj2);
现在obj1包含obj1和obj2的所有值
我扩展了David Coallier的方法:
增加了合并多个对象的可能性支持深层对象override参数(如果最后一个参数是布尔值,则检测到)
如果覆盖为false,则不会覆盖任何属性,但会添加新的财产。
用法:obj.merge(合并…[,覆盖]);
这是我的代码:
Object.defineProperty(Object.prototype, "merge", {
enumerable: false,
value: function () {
var override = true,
dest = this,
len = arguments.length,
props, merge, i, from;
if (typeof(arguments[arguments.length - 1]) === "boolean") {
override = arguments[arguments.length - 1];
len = arguments.length - 1;
}
for (i = 0; i < len; i++) {
from = arguments[i];
if (from != null) {
Object.getOwnPropertyNames(from).forEach(function (name) {
var descriptor;
// nesting
if ((typeof(dest[name]) === "object" || typeof(dest[name]) === "undefined")
&& typeof(from[name]) === "object") {
// ensure proper types (Array rsp Object)
if (typeof(dest[name]) === "undefined") {
dest[name] = Array.isArray(from[name]) ? [] : {};
}
if (override) {
if (!Array.isArray(dest[name]) && Array.isArray(from[name])) {
dest[name] = [];
}
else if (Array.isArray(dest[name]) && !Array.isArray(from[name])) {
dest[name] = {};
}
}
dest[name].merge(from[name], override);
}
// flat properties
else if ((name in dest && override) || !(name in dest)) {
descriptor = Object.getOwnPropertyDescriptor(from, name);
if (descriptor.configurable) {
Object.defineProperty(dest, name, descriptor);
}
}
});
}
}
return this;
}
});
示例和测试用例:
function clone (obj) {
return JSON.parse(JSON.stringify(obj));
}
var obj = {
name : "trick",
value : "value"
};
var mergeObj = {
name : "truck",
value2 : "value2"
};
var mergeObj2 = {
name : "track",
value : "mergeObj2",
value2 : "value2-mergeObj2",
value3 : "value3"
};
assertTrue("Standard", clone(obj).merge(mergeObj).equals({
name : "truck",
value : "value",
value2 : "value2"
}));
assertTrue("Standard no Override", clone(obj).merge(mergeObj, false).equals({
name : "trick",
value : "value",
value2 : "value2"
}));
assertTrue("Multiple", clone(obj).merge(mergeObj, mergeObj2).equals({
name : "track",
value : "mergeObj2",
value2 : "value2-mergeObj2",
value3 : "value3"
}));
assertTrue("Multiple no Override", clone(obj).merge(mergeObj, mergeObj2, false).equals({
name : "trick",
value : "value",
value2 : "value2",
value3 : "value3"
}));
var deep = {
first : {
name : "trick",
val : "value"
},
second : {
foo : "bar"
}
};
var deepMerge = {
first : {
name : "track",
anotherVal : "wohoo"
},
second : {
foo : "baz",
bar : "bam"
},
v : "on first layer"
};
assertTrue("Deep merges", clone(deep).merge(deepMerge).equals({
first : {
name : "track",
val : "value",
anotherVal : "wohoo"
},
second : {
foo : "baz",
bar : "bam"
},
v : "on first layer"
}));
assertTrue("Deep merges no override", clone(deep).merge(deepMerge, false).equals({
first : {
name : "trick",
val : "value",
anotherVal : "wohoo"
},
second : {
foo : "bar",
bar : "bam"
},
v : "on first layer"
}));
var obj1 = {a: 1, b: "hello"};
obj1.merge({c: 3});
assertTrue(obj1.equals({a: 1, b: "hello", c: 3}));
obj1.merge({a: 2, b: "mom", d: "new property"}, false);
assertTrue(obj1.equals({a: 1, b: "hello", c: 3, d: "new property"}));
var obj2 = {};
obj2.merge({a: 1}, {b: 2}, {a: 3});
assertTrue(obj2.equals({a: 3, b: 2}));
var a = [];
var b = [1, [2, 3], 4];
a.merge(b);
assertEquals(1, a[0]);
assertEquals([2, 3], a[1]);
assertEquals(4, a[2]);
var o1 = {};
var o2 = {a: 1, b: {c: 2}};
var o3 = {d: 3};
o1.merge(o2, o3);
assertTrue(o1.equals({a: 1, b: {c: 2}, d: 3}));
o1.b.c = 99;
assertTrue(o2.equals({a: 1, b: {c: 2}}));
// checking types with arrays and objects
var bo;
a = [];
bo = [1, {0:2, 1:3}, 4];
b = [1, [2, 3], 4];
a.merge(b);
assertTrue("Array stays Array?", Array.isArray(a[1]));
a = [];
a.merge(bo);
assertTrue("Object stays Object?", !Array.isArray(a[1]));
a = [];
a.merge(b);
a.merge(bo);
assertTrue("Object overrides Array", !Array.isArray(a[1]));
a = [];
a.merge(b);
a.merge(bo, false);
assertTrue("Object does not override Array", Array.isArray(a[1]));
a = [];
a.merge(bo);
a.merge(b);
assertTrue("Array overrides Object", Array.isArray(a[1]));
a = [];
a.merge(bo);
a.merge(b, false);
assertTrue("Array does not override Object", !Array.isArray(a[1]));
我的equals方法可以在这里找到:JavaScript中的对象比较
如果有人正在使用Google闭包库:
goog.require('goog.object');
var a = {'a': 1, 'b': 2};
var b = {'b': 3, 'c': 4};
goog.object.extend(a, b);
// Now object a == {'a': 1, 'b': 3, 'c': 4};
数组存在类似的助手函数:
var a = [1, 2];
var b = [3, 4];
goog.array.extend(a, b); // Extends array 'a'
goog.array.concat(a, b); // Returns concatenation of array 'a' and 'b'
Use:
//Takes any number of objects and returns one merged object
var objectMerge = function(){
var out = {};
if(!arguments.length)
return out;
for(var i=0; i<arguments.length; i++) {
for(var key in arguments[i]){
out[key] = arguments[i][key];
}
}
return out;
}
测试方法:
console.log(objectMerge({a:1, b:2}, {a:2, c:4}));
结果是:
{ a: 2, b: 2, c: 4 }
基于Markus和vsync的回答,这是一个扩展版本。该函数接受任意数量的参数。它可以用于设置DOM节点上的财产,并对值进行深度复制。然而,第一个论点是通过引用给出的。
要检测DOM节点,使用isDOMNode()函数(请参阅堆栈溢出问题JavaScript isDOM-如何检查JavaScript对象是否为DOM对象?)
它在Opera 11、Firefox 6、Internet Explorer 8和Google Chrome 16中进行了测试。
Code
function mergeRecursive() {
// _mergeRecursive does the actual job with two arguments.
var _mergeRecursive = function (dst, src) {
if (isDOMNode(src) || typeof src !== 'object' || src === null) {
return dst;
}
for (var p in src) {
if (!src.hasOwnProperty(p))
continue;
if (src[p] === undefined)
continue;
if ( typeof src[p] !== 'object' || src[p] === null) {
dst[p] = src[p];
} else if (typeof dst[p]!=='object' || dst[p] === null) {
dst[p] = _mergeRecursive(src[p].constructor===Array ? [] : {}, src[p]);
} else {
_mergeRecursive(dst[p], src[p]);
}
}
return dst;
}
// Loop through arguments and merge them into the first argument.
var out = arguments[0];
if (typeof out !== 'object' || out === null)
return out;
for (var i = 1, il = arguments.length; i < il; i++) {
_mergeRecursive(out, arguments[i]);
}
return out;
}
一些示例
设置HTML元素的innerHTML和样式
mergeRecursive(
document.getElementById('mydiv'),
{style: {border: '5px solid green', color: 'red'}},
{innerHTML: 'Hello world!'});
合并数组和对象。请注意,undefined可用于保存左侧数组/对象中的值。
o = mergeRecursive({a:'a'}, [1,2,3], [undefined, null, [30,31]], {a:undefined, b:'b'});
// o = {0:1, 1:null, 2:[30,31], a:'a', b:'b'}
任何非JavaScript对象的参数(包括null)都将被忽略。除了第一个参数之外,也会丢弃DOM节点。注意,像new String()这样创建的字符串实际上是对象。
o = mergeRecursive({a:'a'}, 1, true, null, undefined, [1,2,3], 'bc', new String('de'));
// o = {0:'d', 1:'e', 2:3, a:'a'}
如果要将两个对象合并为一个新对象(不影响其中任何一个),请提供{}作为第一个参数
var a={}, b={b:'abc'}, c={c:'cde'}, o;
o = mergeRecursive(a, b, c);
// o===a is true, o===b is false, o===c is false
编辑(由收割者很快):
还要合并阵列
function mergeRecursive(obj1, obj2) {
if (Array.isArray(obj2)) { return obj1.concat(obj2); }
for (var p in obj2) {
try {
// Property in destination object set; update its value.
if ( obj2[p].constructor==Object ) {
obj1[p] = mergeRecursive(obj1[p], obj2[p]);
} else if (Array.isArray(obj2[p])) {
obj1[p] = obj1[p].concat(obj2[p]);
} else {
obj1[p] = obj2[p];
}
} catch(e) {
// Property in destination object not set; create it and set its value.
obj1[p] = obj2[p];
}
}
return obj1;
}