Fetch from array of objects

Question

I have an array of objects

var arr = [{id:1, animal:'dog'}, {id:3, animal:'tiger'}, {id:2, animal:'elephant'}, {id:5, animal:'cat'}];

I want to fetch ids from above array of object and make another array like

var idArray = [1,3,2,5]; 

Please suggest a concise es6 solution.

Answer 1

You can do it in one row using map (it will create new array, and will put id from every iteration through arr to idArray ), here it is:

 var arr = [{id:1, animal:'dog'}, {id:3, animal:'tiger'}, {id:2, animal:'elephant'}, {id:5, animal:'cat'}]; var idArray = arr.map(function(item) {return item.id}); console.log(idArray); 

Answer 2

Use Array#map to iterate the array, and pluck the id using an arrow function, and destructuring for the ES6 flavor:

 const arr = [{id:1, animal:'dog'}, {id:3, animal:'tiger'}, {id:2, animal:'elephant'}, {id:5, animal:'cat'}] const result = arr.map(({ id }) => id); console.log(result);