elemOf ()

elemOf<T>(haystack): ((needle) => boolean)
Checks if an element is in an array.
Type Parameters
- T
Parameters
- haystack: readonly T[]
Returns ((needle) => boolean)
A function that takes an element and returns true if it's in the array
- - (needle): boolean
  - Parameters
    - needle: T
    Returns boolean
Example
```
elemOf(['a', 'b'])('a') // true
elemOf([1, 2, 3])(4) // false
opt(1).exists(elemOf([1, 2])) // true
```
See
- Opt.elemOfIn
- elemOfStr
- Defined in Opt.ts:2523