Use the Callback and Closure Pattern to Build Advanced Async Behaviors

In this section, we will introduce another concept to the pattern that we've created:
Operators.
Operators are the final big piece that allows us to bend all asynchronous behaviors to our will. They give us a chance to redefine broadcasters and listeners in any way we want.
We'll several operators throughout this section to implement mapping, filtering, and piping behaviors (and more!).
By the end, you'll get a real sense of how you can continue building on top of the functionality you've already built.
You're in Section 03 of Composing Closures and Callbacks in JavaScript

• Create an Operator Function to Modify Behaviors
• Transform Values with a Map Operator
• Prevent Certain Values with a Filter Operator
• Use Pipe to Clean Up Functions Wrapping Functions
• Start With the API You Want Then Implement
• Define a Function to Set Common Behaviors in Operators
• Use Buffers to Store Values Until a Condition is Met