1.合并数组,其中一项相加(id相同)
let res = []
let arr = JSON.parse(JSON.stringify(this.child))
res = Object.values(arr.reduce((t,c)=>{
(!t[c.id] && (t[c.id]= c)) || (t[c.id] && (t[c.id].num += c.num));
return t;
}, {}));
2.合并数组,找到相同项去重
const res = new Map();
let c = this.child.filter((a)=> !res.has(a.id) && res.set(a.id,1))
3.记录数组的个数,以数组一项作为箭值.组成对象
this.childSel = new Object();
for(let i in this.child){
var id = this.child[i].id
if(this.childSel[id]===undefined){
this.childSel[id] = 1
}else{
this.childSel[id] +=1
}
