Use of filter() array filter in JS

1. Introduction

Array filter is a common method of front-end data processing. For the front-end, we need to process the data returned by the back-end before we can get the data we want and perform further operations. Sometimes the value returned to us by the backend can only be used as a reference.

2. Introduction to the Method

The filter() method creates a new array. The data in the array is the data that meets the conditions after filtering out the specified data.

Two major features of filter()

1.filter() does not detect empty arrays

2.filter() does not change the original array

Usage of filter() method:

array.filter(function(currentValue,index,arr), thisValue)
//currentValue: the value of the current element //index: the subscript of the current element //arr: the original array

3. Usage Examples

1. Get the elements in the array that meet the conditions

const school = [
  {
    occupation:"teacher",
    age:40
  },
  {
    occupation:"student",
    age:23
  },{
    occupation:"Programmer",
    age:1
  }
]
var newShool = school.filter(item => item.age > 20)
console.log(newShool);//[ { occupation: 'Teacher', age: 40 }, { occupation: 'Student', age: 23 } ]

Summarize

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