Javascript / node.js: call a specific function by using the string data from a variable

I am writing a program that automatically finds me information about specific modules for Node.js. At one point, the user enters the function they would like to execute to find information about the object it returns. However, what I'm having trouble with is when I have to call that function. I have found that the following does not work:

• module = the module selected by user
• returningFunction = a string containing the function name

• data = a string with some data to pass into the function

  module.returningFunction(data);

Obviously this doesn't work as returningFunction is a string. What I need to do is somehow make a call to a function using the string data entered into the returningFunction variable. Is this possible?

Thanks.