JavaScript 获取数组最大值的多种实现方式

let arr = [1, 5, 3, 8, 2];
let maxNum = arr[0]; // 假设第一个元素为最大值
for (let i = 1; i < arr.length; i++) {
  if (arr[i] > maxNum) {
    maxNum = arr[i];
  }
}
console.log(maxNum); // 输出 8

let arr = [1, 5, 3, 8, 2];
let maxNum = Math.max.apply(null, arr);
console.log(maxNum); // 输出 8

let arr = [1, 5, 3, 8, 2];
let maxNum = arr.reduce(function(prev, curr) {
  return prev > curr ? prev : curr;
});
console.log(maxNum); // 输出 8

//最小值
Array.prototype.min = function() {
var min = this[0];
var len = this.length;
for (var i = 1; i < len; i++){
if (this[i] < min){
min = this[i];
}
}
return min;
}
//最大值
Array.prototype.max = function() {
var max = this[0];
var len = this.length;
for (var i = 1; i < len; i++){
if (this[i] > max) {
max = this[i];
}
}
return max;
}
//数组长度
var array = new array(1,2,3,2,4,55,2);
alert(array.length);//输出7