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Elements that appear twice in array in JavaScript
We are required to write a JavaScript function that takes in an array of literal values. Our function should pick all those values from the array that appears exactly twice in the array and return a new array of those elements.
Example
The code for this will be −
const arr = [0, 1, 2, 2, 3, 3, 5];
const findAppearances = (arr, num) => {
let count = 0;
for(let i = 0; i < arr.length; i++){
const el = arr[i];
if(num !== el){
continue;
};
count++;
};
return count;
};
const pickAppearingTwice = (arr = []) => {
const res = [];
for(let i = 0; i < arr.length; i++){
const el = arr[i];
if(findAppearances(arr, el) === 2 && !res.includes(el)){
res.push(el);
};
};
return res;
};
console.log(pickAppearingTwice(arr));Output
And the output in the console will be −
[2, 3]
Updated on: 23-Nov-2020
446 Views
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