es6 filter() 数组过滤的方法小结（附代码）

var newarr = [

  { num: 1, val: 'ceshi', flag: 'aa' },

  { num: 2, val: 'ceshi2', flag: 'aa2'  }

]

console.log(newarr.filter(item => item.num===2 ))

var newarr = [

  { num: 1, val: 'ceshi', flag: 'aa' },

  { num: 2, val: 'ceshi2', flag: 'aa2'  }

]

console.log(newarr.filter(item => item.num!=2 ))

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)

var arr = [20,30,50, 96,50]

var newArr = arr.filter(item => item>40) 

console.log(newArr)

var arr = ['10','12','23','44','42']

var newArr = arr.filter(item => item.indexOf('2')<0)

console.log(newArr)

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]