atlantis atlantis - 26 days ago 16
Javascript Question

Is there a way to "require" a JS file only once in nodejs?

I have just started working with nodejs. I wonder if there is a way to "require" a file only once in an app. I am using a class framework for getting classic OOPS in my JS project. Each "class" is contained in its own JS file. I want to "require" the class framework in each file so that they can function independently but want the framework's init code to be executed only once.

I can use a flag to implement this myself but a built-in way would be nice. Search for "require once" leads me to all PHP related questions.

Answer

require is always "require once". After you call require the first time, require uses a cache and will always return the same object.

Any executable code floating around in the module will only be run once.

On the other hand, if you do want it to run initialisation code multiple times, simply throw that code into an exported method.

edit: Read the 'Caching' section of http://nodejs.org/docs/latest/api/modules.html#modules