JavaScript Filter

• Definition
• Filter Tips
• Conclusion

Definition

The filter() method returns new array with all the elements that pass the test implemented by provided function.

Filter Tips

Check below code for filter.

If you have array like this.

const data=[
  {name:"prakash",age:20},
  {name:"bhanu",age:21},
  {name:"mohan",age:40}
];

// Then instead of writing code like this 
const select_user=data.filter(function(user){
    if (user.name==="prakash"){
       return true
    }
    return false
});

You can simplify code as shown it below:

let selected_user=data.filter(function(user) {
    return user.name==="prakash"
})

The above code will return true,if the condition is satisfied otherwise it will return false

We can simplify above code much more simple and understandable using ES6 syntax.

let selected_user=data.filter((user)=> user.name==="prakash")

Conclusion

1. Filter method returns a new array consisting only those
   elements that satisfied the provided function.

2. Filter method does not change original array.

3. Filter method does not execute function for empty elements.

I hope You will learn something from this post.If there are more usecases, please mention in below comment section.

Thanks.

Comments

[Jon Randy 🎖️]

You could further simplify by removing the unnecessary parentheses:

let selected_user=data.filter(user => user.name==="prakash")

[k.Jyothi Prakash Reddy]

Yeah we can do!..

[Giovanni]

Thank you for this post.
I have learned something thanks to you :)

[k.Jyothi Prakash Reddy]

Thanks for commenting.Keep learning!...

[Rob OLeary]

Did you ask for permission to use the image as a cover photo? You can clearly see flaviocopes.com on the bottom?

[k.Jyothi Prakash Reddy]

Thanks for informing me.I changed cover photo.

[k.Jyothi Prakash Reddy]

Thanks @lukeshiru for giving more suggestions !..