The document provides best practices for writing quality code, including following style guides, using consistent naming conventions, writing single-purpose functions and modules, avoiding magic numbers, using abstraction, and following principles like the Twelve-Factor App methodology. It emphasizes writing clean, readable code through practices like descriptive naming, separating concerns, and removing duplication.

1. BEST PRACTICES
FOR
QUALITY CODE
SERCAN DEĞİRMENCİ

2. AGENDA
• BASICS
• IN-DEEP
• EXAMPLE

3. GLOSSARY

4. There are two hard things in
computer science: cache
invalidation, naming things,
and off-by-one errors

5. UNIX
PHILO
SOPHY
that do one thing
and do it well.
to work together.
to handle text streams.
Write programs

6. Fundamental Theorem of
Software Engineering
We can solve any problem by
introducing an extra level of
indirection.

7. ONE and ONLY
SOURCEOF
TRUTH

8. Any fool can write code that a
computer can understand. Good
programmers write code that
humans can understand
Martin Fowler

9. NAMING THINGS

10. FOLLOW THE STYLE GUIDE
• JS: https://github.com/airbnb/javascript
• C++: https://google.github.io/
styleguide/cppguide.html
• Java: https://google.github.io/
styleguide/javaguide.html

11. NAMING CONVENTIONS
• CamelCase
• camelCase
• snake_case

13. FUNCTION NAMES
• Function names should be verb
• DoThing, MakeAbc, GetAbc, SetHello
• Property names should be noun and adj

14. GET-SET
• GET does not get input
• SET gets single input
get hello() {
return this._h;
}
set hello(value) {
this._h = value
}
var center: Int {
get {
return 0
}
set(newValue) {
}
}

15. const games = await api.games();
// TODO(burak): fix name
this.getGamesData(games);
const categories = await api.categories();
// TODO(burak): fix name
this.getCategoriesData(categories,this.state
.games);

16. NAME AND CONTEXT
• Name and context of func/property/class
have to be consistent and meaningful

17. UNIX PHILOSOPHY

18. FUNCTIONS/CLASSES
SHOULD DO ONE THING

19. PACKAGES/MODULES
SHOULD DO ONE THING

21. SOURCE OF TRUTH

22. STRING IS YOUR
WORST ENEMY

25. NO MAGICAL
NUMBERS

27. Magical Number
Will be Broken

28. ABSTRACTION

29. openVerbConjunction(wordObj) {
this.conjArr = [];
let language = this.$scope.global.language;
if (language == "tr") {
CONSTANT.CONJTYPE[language].forEach(c => {
let conjable = {
title: this.conj.conjTurkish(wordObj.title, c),
tence: c
};
this.conjArr.push(conjable);
});
} else if (language == "en") {
CONSTANT.CONJTYPE[language].forEach(c => {
let conjable = {
title: this.conj.conjEnglish(wordObj.title, c),
tence: c
};
this.conjArr.push(conjable);
});
}
document.getElementById("verbConj").style.display = "block";
}
Before

30. openVerbConjunction(wordObj) {
this.conjArr = [];
this.conj.conjtype.forEach(c => {
let conjable = {
title: this.conj.conjVerb(wordObj.title, c),
tence: c
};
this.conjArr.push(conjable);
});
document.getElementById("verbConj").style.display = "block";
}
After

31. protocol RandomNumberGenerator {
func random() -> Double
}
type RandomNumberGenerator interface{
Random() float64
}
interface RandomNumberGenerator{
double Random();
}
class RandomNumberGenerator {
virtual double random() = 0;
}
Abstraction on different programming languages

32. WRAPPER
• Wrap original object
• Add new functionalities

33. export class Category {
constructor(obj) {
this.c = obj;
this._color = null;
this._games = [];
}
locale(lang) {
for (const o of this.c.locales) {
if (o.language === lang) {
return o;
}
}
const dl = this.defaultLanguage;
if (typeof dl === 'string') {
for (const o of this.c.locales) {
if (o.language === dl) {
return o;
}
}
}
return this.c.locales[0];
}
get color() {
if (this._color !== null) {
return this._color;
}
if (typeof this.c.labels.color === 'string
this._color = this.c.labels.color;
} else {
this._color =
colors[Math.floor(Math.random() * colors.lengt
}
return this._color;
}

34. THE TWELVE-FACTOR APP
https://12factor.net/

35. • USE GIT
• USE NPM, YARN
• STORE CONFIG IN THE ENVIRONMENT
• MAKE THE APP STATELESS

36. Don’t use hard-coded values