CHAPTER 13
Functions and the Power of
Abstract Thinking
If JavaScript were a Broadway play, functions would be the glittering starlet: they
would hog the spotlight and take the last bow to thunderous applause (and some
boos, no doubt: you can’t please everyone). We covered the mechanics of functions in
, but now we’re going to consider the ways functions can be used, and how
they can transform your approach to solving problems.
The very concept of a function is chameleon-like: it takes on different aspects when
viewed in different contexts. The first—and simplest—perspective on functions we’re
going to consider is that of a code reuse vehicle.
Functions as Subroutines
The idea of subroutines is a very old one, a practical concession to managing com‐
plexity. Without subroutines, programming would be a very repetitive affair indeed.
Subroutines simply package some bit of repetitive functionality, give it a name, and
allow you to execute that bit of functionality at any time simply by referring to that
name.
Other names for a subroutine are procedure, routine, subprogram,
macro, and the very bland and generic callable unit. Note that in
JavaScript, we don’t actually use the word subroutine. We just call a
function a function (or a method). We’re using the term subroutine
here to emphasize this simple use of functions.
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