Finding the number of unique objects in an array in Angular 7

Question

Say I have a following array which contains the following objects:

array = [{name: 'foo', number: 1}, {name: 'foo', number: 1}, {name: 'bar', number: 1}]

How would I go about finding the number of foo in this array? I am currently doing

search(name, array) {
    let count = 0;
    for (let i = 0; i < array.length; i++) {
      if (array[i].name=== name) {
        count++;
      }
    }
    return count;
  }

I would like to be able to run the search() function and be able to get the number of objects which has name foo and the number of objects which has name bar instead of having to pass in the name of the object itself.

Jelle · Accepted Answer · 2019-01-22 12:35:41Z

3

let array = [{
  name: 'foo',
  number: 1
}, {
  name: 'foo',
  number: 2
}, {
  name: 'bar',
  number: 1
}]

function count(input) {
  var output = {};

  array.forEach(item => {
    if (output[item.name]) {
      output[item.name] += item.number;
    } else {
      output[item.name] = item.number;
    }
  });

  return output;
}

var result = count(array);
console.log(result);

You can iterate over the items and add the counts for each name that is the same. Hope this is what you were looking for, otherwise let me know

answered Jan 22, 2019 at 12:35

Jelle

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1 Comment

Ziv Ofir Over a year ago

Yes, this was exactly what I was looking for! Thanks!

Sachila Ranawaka · Accepted Answer · 2019-01-22 12:17:39Z

1

Use the filter function

let array = [{name: 'foo', number: 1}, {name: 'foo', number: 1}, {name: 'bar', number: 1}]

let count = array.filter(e => e.name === "foo").length;
console.log(count)

answered Jan 22, 2019 at 12:17

Sachila Ranawaka

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