Function pushIfNotExists

pushIfNotExists(array: unknown[], element: unknown): boolean
Insert a element into an array if the element not exists.
Parameters
- array: unknown[]
  The target array.
- element: unknown
  The element to insert.
Returns boolean
It returns true if the element was inserted.
Example
```
const mynumbers = [0, 1, 2]
console.log(PUtilsArray.distinct(mynumbers, 3)) // true
console.log(PUtilsArray.distinct(mynumbers, 3)) 
```
- Defined in putils/array.ts:499