some 原理


let arr = [20, 40, 60];
Array.prototype.mysome = function (fn) {
  for (let i = 0; i < this.length; i++) {
    let flag = fn(this[i],i,this);
    if (flag) {
      return flag;
    }
  }
  return false;
};

let r = arr.mysome(item=>item>50);
console.log(r)


every 原理


let arr = [20, 40, 60];
Array.prototype.myevery = function (fn) {
  let flag = true;
  for (let i = 0; i < this.length; i++) {
    let flag = fn(this[i],i,this);
    if (!flag) {
      return flag;
    }
  }
  return flag;
};

let r = arr.myevery((item,i)=>{
  return item > 20
});
console.log(r)



带你入门前端
38 声望2 粉丝

通俗易懂,言简意赅授课