Function allTrue

allTrue(values?): boolean
Returns whether all the given elements are true
Parameters
- Optionalvalues: (
      | undefined
      | null
      | string
      | number
      | boolean)[]
  the elements to check
Returns boolean
whether all the given elements are true
Example
```
allTrue([null, undefined]);    // false
allTrue([null, true]);    // false
allTrue([true, true]);    // true
```