Sort array of objects by single key with date value

Question

I have an array of objects with several key value pairs, and I need to sort them based on \'updated_at\':

[
    {
        \"updated_at\" : \"2012-01-01T06:25         


        

Answer 1

• Use Array.sort() to sort an array
• Clone array using spread operator (…) to make the function pure
• Sort by desired key (updated_at)
• Convert date string to date object
• Array.sort() works by subtracting two properties from current and next item if it is a number / object on which you can perform arrhythmic operations

const input = [
  {
    updated_at: '2012-01-01T06:25:24Z',
    foo: 'bar',
  },
  {
    updated_at: '2012-01-09T11:25:13Z',
    foo: 'bar',
  },
  {
    updated_at: '2012-01-05T04:13:24Z',
    foo: 'bar',
  }
];

const sortByUpdatedAt = (items) => [...items].sort((itemA, itemB) => new Date(itemA.updated_at) - new Date(itemB.updated_at));

const output = sortByUpdatedAt(input);

console.log(input);
/*
[ { updated_at: '2012-01-01T06:25:24Z', foo: 'bar' }, 
  { updated_at: '2012-01-09T11:25:13Z', foo: 'bar' }, 
  { updated_at: '2012-01-05T04:13:24Z', foo: 'bar' } ]
*/
console.log(output)
/*
[ { updated_at: '2012-01-01T06:25:24Z', foo: 'bar' }, 
  { updated_at: '2012-01-05T04:13:24Z', foo: 'bar' }, 
  { updated_at: '2012-01-09T11:25:13Z', foo: 'bar' } ]
*/