function clone(obj) {
// Handle the 3 simple types, and null or undefined
if (null == obj || "object" != typeof obj) return obj;
// Handle Date
if (obj instanceof Date) {
var copy = new Date();
copy.setTime(obj.getTime());
return copy;
}
// Handle Array
if (obj instanceof Array) {
var copy = [];
for (var i = 0, var len = obj.length; i < len; ++i) {
copy[i] = clone(obj[i]);
}
return copy;
}
// Handle Object
if (obj instanceof Object) {
var copy = {};
for (var attr in obj) {
if (obj.hasOwnProperty(attr)) copy[attr] = clone(obj[attr]);
}
return copy;
}
throw new Error("Unable to copy obj! Its type isn't supported.");
}
// 原数组
var arr = ["One","Two","Three"];
// 使用Array原型上的slice()方法
var arrtoo = arr.slice(0);
// 使用Array原型上的concat方法
var arrtooo = arr.concat();
var obj = { a: 1 };
var copy = Object.assign({}, obj);
console.log(copy); // { a: 1 }
针对深拷贝,需要使用其他方法,因为 Object.assign()拷贝的是属性值。假如源对象的属性值是一个指向对象的引用,它也只拷贝那个引用值
function deepCopy (source) {
var result={};
for (var key in source) {
result[key] = typeof source[key]==='object'? deepCoyp(source[key]): source[key];
}
return result;
}