ES6 必须要用的数组Filter() 方法，不要再自己循环遍历了！！！

1，来一个最简单最常用的栗子：

获得年龄为9岁的孩子

复制代码 1 let arr = [ 2 { 3 name:'小明', 4 sex:0, 5 age:9 6 }, 7 { 8 name:'小红', 9 sex:1, 10 age:9 11 }, 12 { 13 name:'小亮', 14 sex:0, 15 age:10 16 } 17 ] 18 console.log(arr.filter(item => item.age === 9));

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1   let arr = [
 2     {
 3       name:'小明',
 4       sex:0,
 5       age:9
 6     },
 7  { 8 name:'小红', 9 sex:1, 10 age:9 11  }, 12  { 13 name:'小亮', 14 sex:0, 15 age:10 16  } 17  ] 18 console.log(arr.filter(item => item.age === 9));

结果为：[ { name: '小明' , sex: 0, age: 9 }, { name:'小红' , sex: 1, age: 9 } ]

filter方法的返回值为符合过滤条件的元素；

2，去掉数组空字符串、undefined、null

复制代码1 let arr2 = [ 1,3,5,null,4,undefined,10,'hahah','','end' ]; 2 3 console.log(arr2.filter(item => item));

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1   let arr2 = [ 1,3,5,null,4,undefined,10,'hahah','','end' ];
2 
3   console.log(arr2.filter(item => item));

结果为：[1, 3, 5, 4, 10, "hahah", "end"]

3，数组去重的用法

复制代码1 let arr3 = [ 1,3,3,6,5,5,8,9,8,'hahah','wer','hahah' ]; 2 console.log(arr3.filter((item,index,self) => self.indexOf(item) == index));

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1   let arr3 = [ 1,3,3,6,5,5,8,9,8,'hahah','wer','hahah' ];
2   console.log(arr3.filter((item,index,self) => self.indexOf(item) == index));