Answer 1

function add() {
var a = 0;
var out = arguments;

function sum() {
    for(var i = 0; i < arguments.length; i++) {
        a += arguments[i]
    }
    return sum
}

sum.toString = function() {
    for(var i = 0; i < out.length; i++) {
        a += out[i]
    }
    return a;
}

return sum;

}

Answer 2

    function getMax(str) {
      let c = "";
      let res = Array.from(str).reduce((acc, cur) => {
       if (c == cur) {
          acc[cur] = acc[cur] ? acc[cur] + 1 : 2;
        } else {
          acc[cur] = 1;
        }
        c = cur;
        return acc;
      }, {});
      let max = Math.max.apply(null, Object.values(res));
      let ret = {};
      for (let k in res) {
        if (res[k] == max) {
          ret[k] = max;
        }
      }
      return ret;
    }
    console.log(getMax("abbkejsbcccwqaa")); //{c: 3}
    console.log(getMax("abcaakjbb")); //{a: 2, b: 2}

Answer 3

@thereisnowinter dalao 666～萌新学到了新的一手 apply和bind连用，同时绑定调用的方法和调用的主体，只留下一个参数的位置

Answer 4

作者的案列太过简单，应该写那种嵌套比较深的的