ES6 中filter过滤器的用法

var sexData=["男","女","女","男","女"];
var filter2=sexData.filter(function(sex){
	return sex==="女"
})

//console.log(filter2)    ["女", "女", "女"]

var porducts = [
	{name: 'apple',type: 'red'} ,
	{name: 'orange',type: 'orange'},
	{name: 'banana',type: 'yellow'},
	{name: 'mango',type: 'yellow'}
];
var filter2=porducts.filter(function(item){
	return item.type==='yellow'
})
//console.log(filter2)
//0: {name: "banana", type: "yellow"}1: {name: "mango", type: "yellow"}

1. filter()
	返回符合条件的元素的数组[]
	筛选回调函数，有三个参数
	语法：
		array.filter((value, index, arr) => {value === '匹配对象'})
 
特殊用法：
	1. 去掉空字符串、undefined、null
		array.filter((value, index, arr) => {value})
	2. 数组去重
		array.filter((value, index, arr) => {arr.indexOf(value) === index})

//1. 去掉空字符串、undefined、null
var porducts = [
	{name:''},
	{name:"哈哈"}
];
var filter2=porducts.filter(function(item){
	return item.name
})
//console.log(filter2)    
//打印得出  0: {name: "哈哈"}

//2. 数组去重
array.filter((value, index, arr) => {arr.indexOf(value) === index})
var porducts = ['苹果','香蕉','苹果','芒果']
var filter2=porducts.filter(function(item,index,porducts){
	return porducts.indexOf(item)==index
})
//console.log(filter2)
// ["苹果", "香蕉", "芒果"]