How do you access the STDIN input with JavaScript?

How do you access the STDIN input so that I can save it into a variable? (I'm using JavaScript).

Embarrassingly, I'm on the second task of the Beginner's Coding Challenge:
Scan name of user and say Hello

*Write a program to scan the name of the user and say hello to them.
Example input:
Peter

Example output:
Hello Peter*

While I can write a program that works in a generic console (using the prompt method), I can't get it to run in the OneCompiler, because it says prompt is not defined. So I take it that the STDIN input is replacing the actual mode of input, in which case, how can I refer to the STDIN input in my code, so that I can complete the challenge?