Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
This is a follow up question to This Question.
I like (and understand) the solution there. However, in the code I am working in, another way to solve the same problem is used:
function exist(sFN) { if(self[sFN]) return true; return false; } It seems to work fine, although I don’t understand how. Does it work? How? What are minuses of this approach? Should I switch to solution from the other question?
Your condition is checking the existence of the ‘sFN’ property in the ‘self’ object. Anything that isn’t null, undefined, 0, and ” will evaluate to true.
As others have said, you can use typeof, or instanceof to see if it’s actually a function.
Looking at your linked example, you should read up on the difference between ==/!= and ===/!== in javascript. Short answer: (” == null) is true, (” === null) is false.