find unique values in array and count javascript

Question

so i have an array like this, that i want to find the unique value with then count:

users: 
   [ '21000316',
     '21000316',
     '21000316',
     '21000316',
     '22000510',
     '22000510',
     '22000510',
     '22000510' ]

is it possible for me to get the unique value and count it from the array without using sort()? and turn it into this value i try some code but only get the count and the unique value separetely:

{'21000316':4,'21000510':4}

Check this, https://stackoverflow.com/a/49156466/7785337 . Just replace the array values with your's, you ll get the result. — Maniraj Murugan, Nov 15 '22 at 04:50
Possible duplicate of https://stackoverflow.com/q/15052702/7785337 — Maniraj Murugan, Nov 15 '22 at 05:00

Finbar · Accepted Answer · 2022-11-15T04:51:18.003

2

Probably a better approach but you can create an object and then sort through all array elements adding +1 to the object.

const users = ['1', '1', '2', '3', '3', '3', '3'];
const result = {};

for(const user in users)
  result[users[user]] = (result[users[user]] || 0) + 1;

console.log(result);

edited Nov 15 '22 at 04:51

answered Nov 15 '22 at 04:44

Finbar

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it return this :{ '2022-11-12': 1, '2022-11-14': 1 } – JS24 Nov 15 '22 at 04:47
Refresh your answer – Finbar Nov 15 '22 at 04:47

Allan Wind · Answer 2 · 2022-11-15T19:06:41.680

1

const users = [
     '21000316',
     '21000316',
     '21000316',
     '21000316',
     '22000510',
     '22000510',
     '22000510',
     '22000510'
];
console.log(users.reduce((m, k) => { m[k] = m[k] + 1 || 1; return m }, {}));

edited Nov 15 '22 at 19:06

answered Nov 15 '22 at 04:54

Allan Wind

23,068
5
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38

score 1 · Answer 3 · answered Nov 15 '22 at 04:59

let users =  [ '21000316',
     '21000316',
     '21000316',
     '21000316',
     '22000510',
     '22000510',
     '22000510',
     '22000510' ];
     
let set = new Set(users);

let res = [...set.keys()].reduce((pre, cur) => {
    pre[cur] = users.filter(u => u === cur).length;
    return pre;
}, {})

console.log(res)

find unique values in array and count javascript

3 Answers3