Object 物件

Node.js Object 物件
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物件函式

变数 说明
Object.keys() 物件所有键值
Object.values() 物件所有数值
Object.entries() 把物件转为阵列
Object.fromEntries() 把阵列转为物件
Object.assign() 複製物件
Object.hasOwnProperty() 是否是物件本身的属性
Object.gerOwnPropertyDescriptors() 得到这个物件内容值的一些属性
Object.setPrototypeOf() 设定物件原型
Object.getPrototypeOf() 取的物件原型

Object.entries 把物件转为阵列

const Employee = {
    name: 'KJ',
    age: 17
}

// [ [ 'name', 'KJ' ], [ 'age', 17 ] ]
console.log(Object.entries(Employee))

Object.gerOwnPropertyDescriptors 得到这个物件内容值的一些属性

const Employee = {
    name: 'KJ',
    age: 17,
    sayHi : () => {
        console.log(`Hi`)
    }
}

// {
//     name: { value: 'KJ', writable: true, enumerable: true, configurable: true },
//     age: { value: 17, writable: true, enumerable: true, configurable: true },
//     sayHi: {
//         value: [Function: sayHi],
//         writable: true,
//             enumerable: true,
//             configurable: true
//     }
// }
console.log(Object.getOwnPropertyDescriptors(Employee));

assign 複製物件

const target = { a: 1, b: 2 };
const source = { b: 4, c: 5 };

const returnedTarget = Object.assign(target, source);

console.log(target);
// expected output: Object { a: 1, b: 4, c: 5 }

console.log(returnedTarget);
// expected output: Object { a: 1, b: 4, c: 5 }

使用 Object.assign 複製物件

const Employee = {
    name: 'KJ',
    age: 17,
    sayHi : () => {
        console.log(`Hi`)
    }
};

// 使用 Object.assign 複製物件
NewEmployee = Object.assign({}, Employee);
NewEmployee.name = 'Kay';
NewEmployee.age = 19;

// { name: 'KJ', age: 17, sayHi: [Function: sayHi] }
console.log(Employee);
// { name: 'Kay', age: 19, sayHi: [Function: sayHi] }
console.log(NewEmployee);

使用运算元 ... 合併物件

let person = {
  name: 'KJ',
  age: 17,
};


let job = {
    jobTitle: 'Software Engineer',
    location: 'Taiwan'
};

let employee = {
    ...person,
    ...job
};

console.log(employee);

// {
//   name: 'KJ',
//   age: 17,
//   jobTitle: 'Software Engineer',
//   location: 'Taiwan'
// }

后来的物件资料会复盖前面的物件资料

let person = {
  name: 'KJ',
  age: 17,
  jobTitle: 'No Job',
};


let job = {
    jobTitle: 'Software Engineer',
    location: 'Taiwan'
};

let employee = {
    ...person,
    ...job
};

console.log(employee);

// {
//   name: 'KJ',
//   age: 17,
//   jobTitle: 'Software Engineer',
//   location: 'Taiwan'
// }

参考资料