Return the next higher prime number

// This challenge is a little bit more complex
// Write a function that takes a number (a) as argument
// If a is prime, return a
// If not, return the next higher prime number
function
myFunction
(
a
)
{

return
}
Test Cases:
myFunction(38)
Expected
41
myFunction(7)
Expected
7
myFunction(115)
Expected
127
myFunction(2000)
Expected
2003