Javascript - Count array objects that have a value

Question

I\'m getting an array returned to me and I need to count the rows that have a value in them

I\'ve tried to call arr.length but that gives me the total length of the

Answer 1

Foreach through the array and check if the id key has a value

var output = 0;
var arr = [ { id: '1', '': '' },{ id: '2', '': '' },{ id: '3', '': '' },{ id: '4', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' },{ id: '', '': '' } ]

arr.forEach(e => {
  if (e["id"] != '') {
    output++;
  }
});

console.log(output);

Answer 2

if you are a fan of Lodash, you can use countBy (documentation)

const array = [{id:'1','':''},{id:'2','':''},{id:'3','':''},{id:'4','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''},{id:'','':''}]

// The iterator function `obj => obj.id === ''` returns Boolean value `true` or `false`
const count = _.countBy(array, obj => obj.id !== '');

// Get the `true` value
console.log(count.true);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.js"></script>

One liner fans:

_.countBy(array, obj => obj.id !== '').true;