FirstRecurringChar
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const arr1 = [2,1,1,2,3,3,1,3]
const firstRecurringChar = (anArr) => {
let res;
let recurred = {};
for(const elem of anArr){
if (recurred[elem]) return elem
else recurred[elem] = true
}
return res
}
console.log(firstRecurringChar(arr1));
JavaScript
INFO