Object array clone with subset of properties

Question

What is the most efficient way in JavaScript to clone an array of uniform objects into one with a subset of properties for each object?

UPDATE

Would this be the most efficient way to do it or is there a better way? -

var source = [
 {
 id: 1,
 name: 'one',
 value: 12.34
 },
 {
 id: 2,
 name: 'two',
 value: 17.05
 }
];
// copy just 'id' and 'name', ignore 'value':
var dest = source.map(function (obj) {
 return {
 id: obj.id,
 name: obj.name
 };
});

• artm: possible duplicate of How to get a subset of a javascript object's properties
• vitaly-t: @artm, that question is about one object, while I'm asking about an array of objects.
• vitaly-t: @Khalid, that question doesn't cover sub-set of properties.
• artm: Well, you could use stackoverflow.com/a/17781590/3309109 for example and call it for each object in your array.

Answer 1

using Object Destructuring and Property Shorthand

let array = [{ a: 5, b: 6, c: 7 }, { a: 8, b: 9, c: 10 }];
let cloned = array.map(({ a, c }) => ({ a, c }));
console.log(cloned); // [{ a: 5, c: 7 }, { a: 8, c: 10 }]

Answer 2

First define a function that clone an object and return a subset of properties,

Object.prototype.pick = function (props) {
 return props.reduce((function (obj, property) {
 obj[property] = this[property];
 return obj;
 }).bind(this), {});
}

Then define a function that clone an array and return the subsets of each object

function cloneArray (array, props) { 
 return array.map(function (obj) { 
 return obj.pick(props);
 });
}

Now let's say you have this array :

var array = [
 { name : 'khalid', city : 'ifrane', age : 99 },
 { name : 'Ahmed', city : 'Meknes', age : 30 }
];

you need to call the function and pass the array of properties you need to get as result

cloneArray(array, ['name', 'city']);

The result will be :

[
 { name : 'khalid', city : 'ifrane' },
 { name : 'Ahmed', city : 'Meknes' }
]

• vitaly-t: That's even more generic an answer than I was looking for, i.e. I didn't mind specifying columns during the copy operation. Your answer is more reusable and clean. Thank you!

Answer 3

Performance-wise, that would be the most efficient way to do it, yes.

• vitaly-t: Thank you! I did an update after the first answer, which gives a very good and more generic approach.