Home > Article > Web Front-end > How to implement the es6 filter() method? Usage introduction
The filter() method creates a new array, and the elements in the new array are checked for all elements in the specified array that meet the conditions.
es6 Usage of filter() method
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. Remove empty spaces Array empty string, undefined, null
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)
3. Remove non-conforming items in the array
var arr = [20,30,50, 96,50] var newArr = arr.filter(item => item>40) console.log(newArr)
4. Filter non-conforming items
var arr = ['10','12','23','44','42'] var newArr = arr.filter(item => item.indexOf('2')<0) console.log(newArr)
5. 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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