深度克隆

 原始对象如下：

let obj = {
        name: 'tw',
        age: 12,
        fit: ['12', '45', 78],
        git: {
            name: 'github',
            www: 'http:.',
            hub: {
                name: "yu"
            }
        }
    }

封装一个函数用来克隆对象：

function deepClone(origin, target) {
        let toStr = Object.prototype.toString,
            arrStr = '[object Array]';
        for (let prop in origin) {
            if (origin.hasOwnProperty(prop)) {
                if (typeof (origin[prop]) == 'object') {
                    if (toStr.call(origin[prop]) == arrStr) {
                        target[prop] = [];
                    } else {
                        target[prop] = {};
                    }
                    deepClone(origin[prop], target[prop])
                } else {
                    target[prop] = origin[prop];
                }
            }
        }
    }