Things to avoid in JavaScript (the bad parts)
New Course Coming Soon:
Get Really Good at Git
A quick list of things to avoid when writing JavaScript code
- Avoid creating a new object by using
new Object()
. Use the object literal syntax{}
instead. - Same thing for arrays, favor
[]
overnew Array()
. - Avoid blocks except where statements require them (
if
,switch
, loops,try
). - Never assign inside an
if
ofwhile
statements condition part - Never use
==
and!=
. Use===
and!==
instead. - Never use
eval
. Why? It has performance issues (it runs the interpreter/compiler), it has security issues (code injection if used with user input), difficulties in debugging. - Never use
with
, as it modifies the scope chain and can be a source of confusion. - Always pass functions to
setTimeout
andsetInterval
- Never use
Array
as an associative arrays, useObject
instead. The part of theArray
object that provides that functionality is in fact provided by theObject
prototype, so you could really have used aDate
object for that same thing. - Don’t use
\
at the end of a string to create a multiline string, it’s not part of ECMAScript. Use string concatenation' string1 ' + ' string2 '
instead - Never modify the prototypes of the built-in objects
Object
andArray
. Modify other prototypes of other objects such asFunction
with caution as it could lead to bugs hard to debug.
Are you intimidated by Git? Can’t figure out merge vs
rebase? Are you afraid of screwing up something any time
you have to do something in Git? Do you rely on ChatGPT
or random people’s answer on StackOverflow to fix your
problems? Your coworkers are tired of explaining Git to
you all the time? Git is something we all need to use,
but few of us really master it. I created this course to
improve your Git (and GitHub) knowledge at a radical
level. A course that helps you feel less frustrated with
Git. Launching May 21, 2024. Join the waiting list!
→ Get my
JavaScript Beginner's Handbook
→ Read my
JavaScript Tutorials
on The Valley of Code
→ Read my
TypeScript Tutorial
on The Valley of Code
Here is how can I help you:
- COURSES where I teach everything I know
- THE VALLEY OF CODE your web development manual
- BOOTCAMP 2024 cohort in progress, next edition in 2025
- BOOKS 16 coding ebooks you can download for free on JS Python C PHP and lots more
- SOLO LAB everything I know about running a lifestyle business as a solopreneur
- Interesting links collection
- Follow me on X