// --- Directions

// Given a string, return the character that is most

// commonly used in the string.

// --- Examples

// maxChar("abcccccccd") === "c"

// maxChar("apple 1231111") === "1"

function maxChar(str) {

  let m = {},

    max = -1,

    result = null;

  for (let char of str) {

    m[char] = m[char] + 1 || 1;

  }

  for (let [key, count] of Object.entries(m)) {

    max = Math.max(max, count);

    if (max === count) {

      result = key;

    }

  }

  return result;

}

module.exports = maxChar;

const maxChar = require('./index');

test('maxChar function exists', () => {

  expect(typeof maxChar).toEqual('function');

});

test('Finds the most frequently used char', () => {

  expect(maxChar('a')).toEqual('a');

  expect(maxChar('abcdefghijklmnaaaaa')).toEqual('a');

});

test('Works with numbers in the string', () => {

  expect(maxChar('ab1c1d1e1f1g1')).toEqual('1');

});