如何使用扩展运算符创建要在forEach循环中添加到JavaScript对象的动态键

Question

var arr= [{name:'xyz'},{name:'abc'}];

arr.forEach(function(a){
    a.age = 25;
    a.country = 'USA'
    a.technology = 'JavaScript'
});

How can I add these dynamic key-value pair with spread operator using ES6 syntax

Answer 1

 arr = arr.map(prev => ({ ...prev, age: 25, country:"USA" }));

Answer 2

I don't think you can use spread syntax to modify an object, only to create a new object. If you want something that allows you to use a Javascript object literal to modify, use Object.assign()

arr.forEach(a => Object.assign(a, {
    age: 25,
    country: 'USA',
    technology: 'Javascript'
}));

Answer 3

Simply use this code:

var arr= [{name:'xyz'},{name:'abc'}];

var obj =  {
    age: 25,
    country: 'USA',
    technology: 'JavaScript'
};

arr.forEach(function(a){
    Object.assign(a, obj);
});

console.log(arr);