JavaScript浅拷贝和深拷贝递归

浅拷贝的结果是两个引用指向同一个对象，即同一片内存区域。

浅拷贝

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var Ethan = {name: 'xia.weihua', height: '177cm', girlfriend: {name: 'leftHand'}};  // Just a joke, never mind.
var Jack = Ethan;

Jack.height = '165cm';

console.log(Ethan); 
console.log(Jack);
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{ name: 'xia.weihua',
  height: '165cm',     // I'm not
  girlfriend: { name: 'leftHand' } }
{ name: 'xia.weihua',   
  height: '165cm',
  girlfriend: { name: 'leftHand' } }

深拷贝

深拷贝的结果是两个引用指向不同对象，即不同内存区域。实现深拷贝需要递归

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var Ethan = {name: 'xia.weihua', height: '177cm', girlfriend: {name: 'leftHand'}};
var Jack;

function deepCopy(obj) {
    var temp = obj.constructor === Array ? [] : {};
    if (typeof obj !== 'object') {
        return obj;
    } else {
        for (var i in obj) {
            temp[i] = deepCopy(obj[i]);
        }
    }
    return temp;
}

Jack = deepCopy(Ethan);
Jack.name = 'Jack Neo';
Jack.height = '165cm';
Jack.girlfriend.name = 'rightHand';


console.log(Ethan);
console.log(Jack);

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{ name: 'xia.weihua',
  height: '177cm',
  girlfriend: { name: 'leftHand' } }
{ name: 'Jack Neo',
  height: '165cm',
  girlfriend: { name: 'rightHand' } }

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