How to return index and value of the specific element from array on callback using any JavaScript array function?

Question

I tried with filter() function but I'm not sure about returning index and value using that. here's sample code that I tried.

var names = ['A', 'B', 'C', 'D', 'E', 'F', 'G']
const name = names.filter((name, index) => name === 'G' ? console.log(${index}: ${name}) : null)

here variable name is useless because on call back I'm returning nothing. However, I can access index and name inside callback but not sure about returning both.

gurvinder372 · Accepted Answer · 2018-02-23 06:36:34Z

1

Use findIndex instead

var names = ['A', 'B', 'C', 'D', 'E', 'F', 'G'];
var valToFind = "G";
const valIndex = names.findIndex( s => s === valToFind );

you already know that the value is valToFind, so no need to return it.

Or as @PaulPro pointed out, if the values are just strings, then simply use

const valIndex = names.indexOf( valToFind );

Or you can wrap it in an object

var output = { name : valToFind, index : names.indexOf( valToFind ) };

edited Feb 23, 2018 at 6:36

answered Feb 23, 2018 at 6:27

gurvinder372

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7 Comments

Paul Over a year ago

If all you're doing is an equality check in the findIndex test you can also just use indexOf: names.indexOf( valToFind )

gurvinder372 Over a year ago

@Paulpro yeah, this is much simpler if the values are going to be a primitive value. Thanks.

Sanjay Shr Over a year ago

Yes we can, But somehow can I return both using callback?

gurvinder372 Over a year ago

@SanjayShr return to whom?

Sanjay Shr Over a year ago

To the variable. I ended up using one more array like this.

var names = ['A', 'B', 'C', 'D', 'E', 'F', 'G'];  let res=[];  const name = names.filter((name, index) => name === 'C' ? res.push(index, value): null)

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