how to get an index of an array if the checked value is in the nested array?

Question

I have an array like this

const myArray = [ [ false ], [ true ], [ false ] ]

i want to get index of an element that has value == true from array above.

so because the true from array above is in the second element, then I want to get 1 as the index result

how to do that ?

have you tried anything? what does not work? do you have only one array with `true`? — Nina Scholz, Jul 01 '20 at 06:53
Does this answer your question? [To find Index of Multidimensional Array in Javascript](https://stackoverflow.com/questions/16102263/to-find-index-of-multidimensional-array-in-javascript) — Heretic Monkey, Jul 01 '20 at 16:24

score 1 · Accepted Answer · answered Jul 01 '20 at 06:59

1

You just need add filter for this,

const myArray = [ [ false ], [ true ], [ false ] ] 

let result = myArray.filter(function(value) {
    return value[0]=== true;
});

answered Jul 01 '20 at 06:59

Hasintha Janka

1

That returns a filtered array, not the index of the array with a true value. – see sharper Jul 01 '20 at 07:15

eemrah · Answer 2 · 2020-07-01T07:04:30.420

1

const arrays = [ [ false ], [ true ], [ false ] ] 

const index = [].concat.apply([], arrays).findIndex(value => value === true)

edited Jul 01 '20 at 07:04

answered Jul 01 '20 at 06:59

eemrah

score 0 · Answer 3 · edited Jul 01 '20 at 16:16

0

const idx = myArray.findIndex(i => i[0]);

edited Jul 01 '20 at 16:16

Donald Duck

answered Jul 01 '20 at 06:53

see sharper

2

Post answer with only code is not good, please explains always your answer. – Simone Rossaini Jul 01 '20 at 13:49
While this code may answer the question, providing additional context regarding how and/or why it solves the problem would improve the answer's long-term value. – Donald Duck Jul 01 '20 at 16:15
The code is so simple I would think it self explanatory, noting that the other answers either offer no explanation, or a rather redundant one-liner. IMO this is still the best answer. The accepted answer is plain wrong, and the other upvoted answer uses a hard to read array flattening technique that *does* need explanation. – see sharper Jul 01 '20 at 23:42

score 0 · Answer 4 · answered Jul 01 '20 at 06:55

0

you can loop on your array with map method


const arr = [ [ false ], [ true ], [ false ] ] 

arr.map((item, index) => {

if (item[0]) {
  console.log(index)
}

})

answered Jul 01 '20 at 06:55

1

`map` returns a new array. if this is not used later, it makes no sense. – Nina Scholz Jul 01 '20 at 07:01

4 Answers4