findMostFreq.js

/**
 * 查找出现频率最高项
 * @param {Array} array
 */
function findMostFreq (array) {
  let freqs = {};
  let length = array.length;
  let result = { item: undefined, freq: 0 };
  for (let i = 0; i < length; i++) {
    let item = array[i];
    let freq = (freqs[item] || 0) + 1;
    freqs[item] = freq;
    if (freq > result.freq) {
      result = { item, freq };
    }
  }
  return result;
}

test.js

let array = [0,1,2,3,4,5,6,0,6,2,3,0,6,2,0];
console.log(findMostFreq(array));