什么是最有效的方式来克隆一个JavaScript对象?我已经看到obj = eval(uneval(o));被使用,但它是非标准的,仅支持Firefox.我做了事情,如obj = JSON.parse(JSON.stringify(o));但质疑效率。
当前回答
function clone(obj)
{ var clone = {};
clone.prototype = obj.prototype;
for (property in obj) clone[property] = obj[property];
return clone;
}
其他回答
// obj target object, vals source object
var setVals = function (obj, vals) {
if (obj && vals) {
for (var x in vals) {
if (vals.hasOwnProperty(x)) {
if (obj[x] && typeof vals[x] === 'object') {
obj[x] = setVals(obj[x], vals[x]);
} else {
obj[x] = vals[x];
}
}
}
}
return obj;
};
我使用npm克隆图书馆,显然它也在浏览器中工作。
https://www.npmjs.com/包装/克隆
let a = clone(b)
单线 ECMAScript 6 解决方案(特殊对象类型如 Date/Regex 未处理):
const clone = (o) => typeof o === 'object' && o!== null? // only clone objects (Array.isArray(o)? // if cloning an array o.map(e => clone(e)) : // clone each of its elements Object.keys(o).reduce( // otherwise reduce every key in the object (r, k) => (r[k] = clone(o[k]), r), {} // and save its cloned value
class Handler { static deepCopy (obj) { if (Object.prototype.toString.call(obj) === '[object Array]') { const result = []; for (let i = 0, len = obj.length; i < len; i++) { result[i] = Handler.deepCopy(obj[i]); } return result; } else if (Object.prototype.toString.call(obj) === '[object Object]') { const result = {}; for (let prop in obj) { result[prop] = Handler.deepCopy(obj[prop]); } return result; } return obj; } }
什么是无与伦比的对象克隆,由一个承诺完成?
async function clone(thingy /**/)
{
if(thingy instanceof Promise)
{
throw Error("This function cannot clone Promises.");
}
return thingy;
}