Arrays - Checking if a key exists in a JavaScript object?

Question:

b" How do I check if a particular key exists in a JavaScript object or array?If a key doesn't exist, and I try to access it, will it return false? Or throw an error? "

Solution : https://worcraft-algeria-dz.com/howto/40/arrays---Checking-if-a-key-exists-in-a-JavaScript-object? | Source : https://worcraft-algeria-dz.com/