在JavaScript中合併對象

Question

我有兩個對象，我想合併它們，但它不應該替換對象。

var x = {'one':1, 'two': {'b': 2, 'c': 3}} 
var y = {'two': {'b': 4}} 

當我把它們合併的放出來應該是：

{'one':1, 'two': {'b': 4, 'c': 3}} 

Answer 1

您可以使用遞歸方法用於更新嵌套對象。

var x = { 
 
    'one': 1, 
 
    'two': { 
 
    'b': 2, 
 
    'c': 3 
 
    } 
 
} 
 
var y = { 
 
    'two': { 
 
    'b': 4 
 
    } 
 
} 
 

 

 
function merge(a, b) { 
 
// create new object and copy the properties of first one 
 
    var res = Object.assign({}, a); 
 
    //iterate over the keys of second object 
 
    Object.keys(b).forEach(function(e) { 
 
    // check key is present in first object 
 
    // check type of both value is object(not array) and then 
 
    // recursively call the function 
 
    if (e in res && typeof res[e] == 'object' && typeof res[e] == 'object' && !(Array.isArray(res[e]) || Array.isArray(b[e]))) { 
 
    // recursively call the function and update the value 
 
    // with the returned ne object 
 
    res[e] = merge(res[e], b[e]); 
 
    } else { 
 
     // otherwise define the preperty directly 
 
     res[e] = b[e]; 
 
    } 
 
    }); 
 
    return res; 
 
} 
 

 
var res = merge(x, y); 
 

 
console.log(res);

---

UPDATE：如果你想在陣列合併，那麼你需要做這樣的事情。

var x = { 
 
    'one': 1, 
 
    'two': { 
 
    'b': [22, 23], 
 
    'c': 3 
 
    } 
 
} 
 
var y = { 
 
    'two': { 
 
    'b': [24] 
 
    } 
 
} 
 

 

 
function merge(a, b) { 
 
    var res = Object.assign({}, a); 
 
    Object.keys(b).forEach(function(e) { 
 
    if (e in res && typeof res[e] == 'object' && typeof res[e] == 'object' && !(Array.isArray(res[e]) || Array.isArray(b[e]))) { 
 
     res[e] = merge(res[e], b[e]); 
 
     // in case both values are array 
 
    } else if (Array.isArray(res[e]) && Array.isArray(b[e])) { 
 
     // push the values in second object 
 
     [].push.apply(res[e], b[e]); 
 
     // or use 
 
     // res[e] = res[e].concat(b[e]); 
 
    } else { 
 
     res[e] = b[e]; 
 
    } 
 
    }); 
 
    return res; 
 
} 
 

 
var res = merge(x, y); 
 

 
console.log(res);