how to map more than one property from array of object in javascript

Question

I have an array of Object as follows:

var obj = [
  {a: 1, b: 5, c: 9},
  {a: 2, b: 6, c: 10},
  {a: 3, b: 7, c: 11},
  {a: 4, b: 8, c: 12}
];

I know about how to get single object using Array.map() like this.

var result = obj.map(x=>x.a)

This will give me following result

[1, 2, 3, 4]

But I want result like follows:

[
  {a: 1, b: 5},
  {a: 2, b: 6},
  {a: 3, b: 7},
  {a: 4, b: 8}
]

In short, from an array of objects I want to select only a few fields (more than one).

How can I do that?

Answer 1

You can use .map() with Object Destructuring:

let data = [
    {a:1,b:5,c:9}, {a:2,b:6,c:10},
    {a:3,b:7,c:11}, {a:4,b:8,c:12}
];
          
let result = data.map(({ a, b }) => ({a, b}));

console.log(result);

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Answer 2

If, as in your example, you want to exclude a particular property or few, you can use destructuring and use rest properties to create an object with only the properties you want:

var obj = [
  {a:1,b:5,c:9},
  {a:2,b:6,c:10},
  {a:3,b:7,c:11},
  {a:4,b:8,c:12}
];
const mapped = obj.map(({ c, ...rest }) => rest);
console.log(mapped);

If you want to include properties, simply extract them from the .map callback:

var obj = [
  {a:1,b:5,c:9},
  {a:2,b:6,c:10},
  {a:3,b:7,c:11},
  {a:4,b:8,c:12}
];
const mapped = obj.map(({ a, b }) => ({ a, b }));
console.log(mapped);