是否有一个聪明的(即优化)方法重命名一个关键在javascript对象?
一种非优化的方式是:
o[ new_key ] = o[ old_key ];
delete o[ old_key ];
是否有一个聪明的(即优化)方法重命名一个关键在javascript对象?
一种非优化的方式是:
o[ new_key ] = o[ old_key ];
delete o[ old_key ];
当前回答
使用对象解构和展开运算符的变体:
const old_obj = {
k1: `111`,
k2: `222`,
k3: `333`
};
// destructuring, with renaming. The variable 'rest' will hold those values not assigned to kA, kB, or kC.
const {
k1: kA,
k2: kB,
k3: kC,
...rest
} = old_obj;
// now create a new object, with the renamed properties kA, kB, kC;
// spread the remaining original properties in the 'rest' variable
const newObj = {kA, kB, kC, ...rest};
对于一个键,这可以很简单:
const { k1: kA, ...rest } = old_obj;
const new_obj = { kA, ...rest }
你也可能喜欢更“传统”的风格:
const { k1, ...rest } = old_obj
const new_obj = { kA: k1, ...rest}
其他回答
简单地这么做会有什么问题吗?
someObject = {...someObject, [newKey]: someObject.oldKey}
delete someObject.oldKey
如果愿意,可以将其包装在函数中:
const renameObjectKey = (object, oldKey, newKey) => {
// if keys are the same, do nothing
if (oldKey === newKey) return;
// if old key doesn't exist, do nothing (alternatively, throw an error)
if (!object.oldKey) return;
// if new key already exists on object, do nothing (again - alternatively, throw an error)
if (object.newKey !== undefined) return;
object = { ...object, [newKey]: object[oldKey] };
delete object[oldKey];
return { ...object };
};
// in use
let myObject = {
keyOne: 'abc',
keyTwo: 123
};
// avoids mutating original
let renamed = renameObjectKey(myObject, 'keyTwo', 'renamedKey');
console.log(myObject, renamed);
// myObject
/* {
"keyOne": "abc",
"keyTwo": 123,
} */
// renamed
/* {
"keyOne": "abc",
"renamedKey": 123,
} */
下面是创建具有重命名键的新对象的示例。
let x = { id: "checkout", name: "git checkout", description: "checkout repository" };
let renamed = Object.entries(x).reduce((u, [n, v]) => {
u[`__${n}`] = v;
return u;
}, {});
使用对象解构和展开运算符的变体:
const old_obj = {
k1: `111`,
k2: `222`,
k3: `333`
};
// destructuring, with renaming. The variable 'rest' will hold those values not assigned to kA, kB, or kC.
const {
k1: kA,
k2: kB,
k3: kC,
...rest
} = old_obj;
// now create a new object, with the renamed properties kA, kB, kC;
// spread the remaining original properties in the 'rest' variable
const newObj = {kA, kB, kC, ...rest};
对于一个键,这可以很简单:
const { k1: kA, ...rest } = old_obj;
const new_obj = { kA, ...rest }
你也可能喜欢更“传统”的风格:
const { k1, ...rest } = old_obj
const new_obj = { kA: k1, ...rest}
在我看来,你的方法是最优化的。但你最终会得到重新排序的密钥。新创建的密钥将附加在末尾。我知道你不应该依赖键的顺序,但如果你需要保存它,你将需要遍历所有键并一个接一个地构造新对象,在这个过程中替换有问题的键。
是这样的:
var new_o={};
for (var i in o)
{
if (i==old_key) new_o[new_key]=o[old_key];
else new_o[i]=o[i];
}
o=new_o;
我认为最完整(和正确)的方法是:
if (old_key !== new_key) {
Object.defineProperty(o, new_key,
Object.getOwnPropertyDescriptor(o, old_key));
delete o[old_key];
}
此方法确保重命名的属性的行为与原始属性相同。
另外,在我看来,把它包装成一个函数/方法,并把它放入对象的可能性。原型与你的问题无关。