Question

How to get the unique values of an array in JavaScript

Answer 1

function arrayUnique(arr) {
    const result = [];
    
    arr.forEach(val => {
        if (!result.includes(val)) {
            result.push(val);
        }
    });
    
    return result;
}

const arr = [1, 2, 1, 1, 3, 3, 4, 4, 5, 5, 5, 5, 6, 7, 7, 8];
const result = arrayUnique(arr);

result.forEach(val => console.log(val));




/*
run:

1
2
3
4
5
6
7
8

*/

 

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Answer 2

function arrayUnique(arr) {
   const result = arr.reduce((acc, value) => {
      if (!acc.includes(value)) {
        acc.push(value);
      }
      return acc;
    }, []);
    
    return result;
}

const arr = [1, 2, 1, 1, 3, 3, 4, 4, 5, 5, 5, 5, 6, 7, 7, 8];

const result = arrayUnique(arr);

console.log(result);




/*
run:

[
  1, 2, 3, 4,
  5, 6, 7, 8
]

*/

 

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