leetCode387v1.js

var firstUniqChar = function(s) {
    var counter = new Map();
    for(let word of s){
        if(word === undefined)
            break;
        if(!(counter.has(word))){
            counter.set(word,1);
        }else{
            counter.set(word,counter.get(word)+1);
        }
    }
    for(let [key,value] of counter){
        if(counter.get(key) === 1){
            return s.search(key);
        }
    }
    return -1;
};
var a = firstUniqChar("leetcode");