Find specific elements in JS array

Question

I have an array of items that looks, for instance, like this:

[el, el, *el*, TARGET, TARGET, TARGET, *el*, el, el, el]

I can't find a way to get previous and subsequent elements relative to the TARGET sequence, i.e both *el*. Number of TARGET element in sequence may vary but the sequence is always concrete i.e TARGET, el, TARGET does not happen. I have access to lodash methods, too, but I couldn't find the correct way to achieve this.

You can do a better explanation ?

Luan Castro
– Luan Castro

2016-03-18 17:41:57 +00:00
Commented Mar 18, 2016 at 17:41 — Luan Castro
– Luan Castro, Commented Mar 18, 2016 at 17:41
A combination of indexOf and lastIndexOf?

Mike Cluck
– Mike Cluck

2016-03-18 17:43:37 +00:00
Commented Mar 18, 2016 at 17:43 — Mike Cluck
– Mike Cluck, Commented Mar 18, 2016 at 17:43
show the array with real values

RomanPerekhrest
– RomanPerekhrest

2016-03-18 17:43:44 +00:00
Commented Mar 18, 2016 at 17:43 — RomanPerekhrest
– RomanPerekhrest, Commented Mar 18, 2016 at 17:43

isvforall · Accepted Answer · 2016-03-18 17:46:58Z

2

You can use indexOf and lastIndexOf:

var arr = ['el', 'el', '*el*', 'TARGET', 'TARGET', 'TARGET', '*el*', 'el', 'el'];

var first = arr[arr.indexOf('TARGET') - 1];
var second = arr[arr.lastIndexOf('TARGET') + 1];

document.write(first + '<br/>');
document.write(second);

edited Mar 18, 2016 at 17:46

answered Mar 18, 2016 at 17:45

isvforall

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1 Comment

kmiyashiro Over a year ago

@dandavis the question specifically says that does not happen.

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