reduce的用法

1. 求数组项之和

let sum = arr.reduce(function (prev, cur) { return prev + cur; },0);

2. 求数组项最大值

let max = arr.reduce(function (prev, cur) { return Math.max(prev,cur); });

3. 数组去重

let newArr = arr.reduce(function (prev, cur) { prev.indexOf(cur) === -1 && prev.push(cur); return prev; },[]);

4.数组对象去重

let newobj = {} let newList = this.arrList.reduce((preVal, curVal) => { newobj[curVal.id] ? '' : (newobj[curVal.id] = preVal.push(curVal)) return preVal }, []);