front-end-developer_1_

Front-End-Developer - Level 1
You might be getting tired of me pointing out the indentation, but I'm going to do it again,
because it's something worth taking your time to do right: everything inside the forEach()
method is indented in two spaces, because it's code that's inside the callback function, and
everything in a function gets indented so that it's obvious what's in the function and what's
outside it.
I'm going to end this lesson with a short lecture. One of the best definitions of "good code"
I've heard comes from Corey Haines, a developer who helps train other developers. The one
thing that's certain about software, according to Corey, is that it changes. There will always
be new features to add and bugs to fix. Often, the people working on the software will
change, and even if they don't, the original developers will need to modify code they wrote
months or years ago, code that they sometimes can't even remember writing.
One of things I really like about the new, looping version of the Madlibs JavaScript is that
there's no repetition in the code, which makes it easy to change. Before, we did the same
thing 6 times: get the value of the input, then put in in the appropriate blank space. If we
want to change something - like, I don't know, capitalize all the text before inserting it onto
the page (obviously this is contrived, but hopefully you get the idea) - then we have to
change all 6 places. In this small example, the only room for error is maybe forgetting to
update one line, although that would be embarrassing. But as your programs get more
complex, you'll see that, if you have repetitive code, it becomes very difficult to maintain, and
you will regularly update one place and fail to update another - or worse yet, update them in
different ways that cause incompatibilities down the road.
There's a principle in software development called Don't Repeat Yourself, or DRY. DRY code
is easy to change, because you only have to make any change in one place. One way we
DRY up our code is by taking repetitive bits of code and extracting them into a function.
Another way is by taking something we do several times and by turning it into a loop.
Whenever you finish writing some code, you should always look back to see if there is any
way you can DRY it up.
Also, remember how I harped on about using descriptive variable names? "Easy to change"
doesn't just mean clean code - if you can't figure out what a variable is for or what a function
does based on its name, then it's harder to change it down the road, when you might not
remember exactly how your code works (or when somebody else is trying to change your
code).
Summary
Simple loop with forEach() :
Looping
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