Count number of negative values in array

// Write a function that takes an array of numbers as argument
// Return the number of negative values in the array
function
myFunction
(
a
)
{

return
}
Test Cases:
myFunction([1,-2,2,-4])
Expected
2
myFunction([0,9,1])
Expected
0
myFunction([4,-3,2,1,0])
Expected
1