let arr = [0,1,2,3,0,2,1,3,7]
let arr1 = arr.reduce(function(pre(上一个值),nav(当前值)){
pre.indexOf(nav) === -1 && pre.push(nav)
return pre
},[])
console.log(arr1)
//去重[ 0, 1, 2, 3, 7 ]
let arr2 = arr.reduce(function(pre,nav){
return Math.max(nav)
})
console.log(arr2)
//最大值:7