Project scenario:
There are several objects in an array,
var arr = [
{name:'王',age:'22'},
{name:'李',age:'16'},
{name:'张',age:'55'},
{name:'郝',age:'45'},
{name:'赵',age:'33'},
{name:'王',age:'22'},
]Now deduplicate the array arr
Problem Description
First of all, the first thing I think of is the simple and easy-to-write ES5 new Set( );
code show as below:
var newarr = [...new Set(arr)];
console.log(newarr);
//[
// {name:'王',age:'22'},
// {name:'李',age:'16'},
// {name:'张',age:'55'},
// {name:'郝',age:'45'},
// {name:'赵',age:'33'},
// {name:'王',age:'22'},
//]It was found that it did not take effect after deduplication
Cause Analysis:
new Set() is only applicable to the basic types in the array, so it cannot be deduplicated
solution:
1. Use reduce to achieve
let obj = {};
newarr = arr.reduce((cur,next) => { //next each item
obj[next.name] ? "" : obj[next.name] = true && cur.push(next);
return cur;
},[]) //Set the default type of cur to an array, and the initial value is an empty array
console.log(newarr);