Find first non repeating char in a string

unique-char.js

// Find first non repeating char in a string

function firstUnique(str) {
  let dict = {};

  for (let i=0; i<str.length; i++) {
    if (dict[str[i]]) {
      dict[str[i]] += 1;
    } else {
      dict[str[i]] = 1;
    }
  }

  let keys = Object.keys(dict);
  for (let i=0; i<keys.length; i++) {
    if (dict[keys[i]] == 1) {
      return keys[i];
      break;
    }
  }
}

let str = 'bcabcdf';
console.log('res = ' + firstUnique(str));