1.reduce去重
语法：reduce(callback,initVal,allArr) initVal为初始值，allArr为原数组
举例：
let a = [1,2,3,2,5,2,6,3];
a.reduce((pre,cur)=>{
if(pre.includes(cur)){
return pre
}else{
return pre.concat(cur)
}
},[])
// [1, 2, 3, 5, 6]
let b =[
{
name:'红红',
id:'121'
},
{
name:'绿绿',
id:'120'
},{
name:'红红',
id:'121'
},{
name:'兰兰',
id:'132'
}
];
let temp =[];
b.reduce((pre,cur)=>{
if(temp.includes(cur.id) == false){
temp = temp.concat(cur.id);
return pre.concat(cur)
}
return pre;
}, [])
//结果： [{name:'红红', id:'121' },{name:'绿绿',id:'120'},{name:'兰兰',id:'132'}];
