return the first non repeating character in a string in javascript

Question

So I tried looking for this in the search but the closest I could come is a similar answer in several different languages, I would like to use Javascript to do it.

T

Answer 1

function firstUniqChar(str) {
    let myMap = new Map();
    for(let i = 0; i < str.length; i++) {
        let char = str.charAt(i);
        if(!myMap.has(char)) {
            myMap.set(char, 0);
        }
        myMap.set(char, myMap.get(char) + 1 );
    }
    for(let [key, value] of myMap) {
       if(value === 1) {
           return key;
       }
    }
    return null;
}

let result = firstUniqChar("caabbdccee");
console.log(result);

You can use Map Object and set key and value, where in value you store the count for that particular character, After that you can iterate over map and check where is value 1 and return that key.

Map Object remembers the original insertion order of the keys.