This article brings you an introduction to the filter() array filtering method in es6 (with code). It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
1. Create an array and determine whether a certain value exists in the array
var newarr = [ { num: 1, val: 'ceshi', flag: 'aa' }, { num: 2, val: 'ceshi2', flag: 'aa2' } ] console.log(newarr.filter(item => item.num===2 ))
2. You can also use the above method to filter out those with num of 2 and leave those with num of 1
var newarr = [ { num: 1, val: 'ceshi', flag: 'aa' }, { num: 2, val: 'ceshi2', flag: 'aa2' } ] console.log(newarr.filter(item => item.num!=2 ))
3. Remove empty strings, undefined, and null from empty arrays
var arr = ['1','2',undefined, '3.jpg',undefined] var newArr = arr.filter(item => item) console.log(newArr)
var arr = ['1','2',null, '3.jpg',null] var newArr = arr.filter(item => item) console.log(newArr)
//空字符串里面不能包含空格 var arr = ['1','2','', '3.jpg',''] var newArr = arr.filter(item => item) console.log(newArr)
4. Remove non-conforming items from the array
var arr = [20,30,50, 96,50] var newArr = arr.filter(item => item>40) console.log(newArr)
5. Filter non-conforming items
var arr = ['10','12','23','44','42'] var newArr = arr.filter(item => item.indexOf('2')<0) console.log(newArr)
6. Array deduplication
var arr = [1, 2, 2, 3, 4, 5, 5, 6, 7, 7,8,8,0,8,6,3,4,56,2]; var arr2 = arr.filter((x, index,self)=>self.indexOf(x)===index) console.log(arr2); //[1, 2, 3, 4, 5, 6, 7, 8, 0, 56]
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