正则语法

  1.     function _morenum(arr) {
  2.       let a = [...new Set(arr)]
  3.       let b = arr.join('')
  4.       let c = []
  5.       for (let i = 0; i < a.length; i++) {
  6.         let d = a[i]
  7.         let reg = `/${d}/g`
  8.         // console.log(b.match(reg));
  9.         c.push({ k: d, v: b.match(eval(reg)).length })
  10.       }
  11.       return c.sort((a, b) => b.v - a.v)[0].k
  12.     }
  13.      console.log(_morenum([1, 2, 1, 1, 1, 2, 2, 2, 2]));

使用Map方法

  1.     function _morenum(arr) {
  2.       let c = new Map()
  3.       let res = 0;
  4.       let key = null
  5.       for (let i = 0; i < arr.length; i++) {
  6.         if (!c.has(arr[i])) {
  7.           c.set(arr[i], 1)
  8.         } else {
  9.           let a = c.get(arr[i])
  10.           c.set(arr[i], ++a)
  11.         }
  12.        if (res < c.get(arr[i])) {
  13.           res = c.get(arr[i])
  14.           key = arr[i]
  15.         }
  16.       }
  17.       return key
  18.    //   for (let i of c) {
  19.    //     if (i[1] == Math.max.apply(null, [...c.values()])) {
  20.    //       return i[0]
  21.    //     }
  22.    //   }
  23.     }
  24.     console.log(_morenum([1, 2, 1, 1, 1, 2, 2, 2, 2]));