javascript filter function - callback function issue

Question

below is javascript code with filter function. when using below code, it works perfectly-

const words = ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present'];

const result = words.filter(word => word.length > 6);

console.log(result);
// expected output: Array ["exuberant", "destruction", "present"]

but below code gives an empty array. Why?

const words = ['spray', 'limit', 'elite', 'exuberant', 'destruction', 'present'];

const result = words.filter((word) => {
word.length > 6;
});

console.log(result);
// expected output: Array ["exuberant", "destruction", "present"]

In the first case, you didn't use a curly brace, so it returns the `word.length > 6` expressions output. But in the 2nd case, you've used curly brace so you have to use the return keyword to return `true/false` explicitly. — Sajeeb Ahamed, Jul 11 '21 at 07:25
So for the 2nd case if you do something like `(word) => { return word.length > 6;}` then it will work. — Sajeeb Ahamed, Jul 11 '21 at 07:26

score 0 · Answer 1 · edited Jul 11 '21 at 07:29

0

Whenever you use curly brackets in callback you should return something

const result = words.filter((word) => {
    return word.length > 6;
});

This will work for you

edited Jul 11 '21 at 07:29

Louys Patrice Bessette

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answered Jul 11 '21 at 07:26

Vijay Thomas

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Can't believe my answer was 10sec slower but same ! – Sanmeet Jul 11 '21 at 07:29
@Sanmeet hehe, I can feel you bro!! – Vijay Thomas Jul 11 '21 at 07:33

score 0 · Accepted Answer · edited Jul 11 '21 at 07:27

0

Actually, you need to return the Boolean value in function so that it filters accordingly

See-

const result = words.filter((word) => {
    return word.length > 6;
});

edited Jul 11 '21 at 07:27

Sajeeb Ahamed

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answered Jul 11 '21 at 07:26

Sanmeet

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javascript filter function - callback function issue

2 Answers2