相關代碼var des = 1;
var obj = {b: 2};
for(var key in obj) {
console.log(des, key); // 1, "b"
des[key] = obj[key]; // ???
console.log(des[key]); // undefined}問題des[key] = obj[key] 這句如何執行？ 代碼并沒有報錯, 但des[key]打印結果是undefined代碼來源function deepCopy(des, src) { if(!src || typeof src !== 'object') { return des;
} for (var key in src) { let obj = src[key]; if(obj && typeof obj === 'object') {
des[key] = des[key] || {};
deepCopy(des[key], obj);
} else {
des[key] = src[key];
}
} return des;
}console.log(deepCopy({a: 1}, {a: {b: 2}})); // {a: 1}console.log(deepCopy({a: {}}, {a: {b: 2}})); // {a: {b: 2}}
請教下面這段代碼具體如何執行
慕無忌1623718
2019-03-02 18:00:52
