js filter array filters

Record what was the use of an array of filters

The filter will create a new array, the array does not change the original

Syntax: Array = new non-empty source array .filter ((entry index, the original array) => {

　　Screening was business logic

})

 

eg：

 

let oldArr = [
    {
        name:'tom',
        age:13
    }, 
   {
        name:'tom2',
        age:14
    }, 
   {
        name:'tom3',
        age:15
    }, 
   {
        name:'tom4',
        age:16
    },
];

let newArr = oldArr.filter((item, index,arr)=>{
    return item.age>15
});

console.log(oldArr.length) //4
console.log(newArr.length) //1