Problem with Return Early Pattern for Functions

I am having an issue solving this challenge

Stated Goal
Modify the function abTest so that if a or b are less than 0 the function will immediately exit with a value of undefined

Objectives
abTest(2,2) should return a number

abTest(2,2) should return 8

abTest(-2,2) should return undefined

abTest(2,-2) should return undefined

abTest(2,8) should return 18

abTest(3,3) should return 12

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