object of keys js code example

Example 1: get keys objet javascript

var foo = {
  'alpha': 'puffin',
  'beta': 'beagle'
};

var keys = Object.keys(foo);
console.log(keys) // ['alpha', 'beta'] 
// (or maybe some other order, keys are unordered).

Example 2: js create object with keys

var users = [{userId: "1", name: 'harald'}, {userId: "2", name: 'jamie'}];    
var obj = {};
users.forEach(user => {
  obj = {
    ...obj,
    [user.userId]: user,
  }
})
console.log(obj)
// {
//   1: {userId: "1", name: "harald"}
//   2: {userId: "2", name: "jamie"}
// }