The document discusses tips for writing clean code, including avoiding bad practices that lead to code smells. It recommends using intention-revealing names, single responsibility principle, DRY principle, small methods and classes, and including comments only in complex algorithms. Code should be readable on its own. Tips to achieve clean code include limiting line counts, avoiding comments by improving code clarity, working in pairs, and using more classes to promote code reuse. The goal is to start refactoring code to apply these principles.

1. Clean Code Tips
September 2013
@JuanmaGomeR

2. How do we code?
It is done when (we think) it
is working.
We invest the minimum
amount time to get the best
results.
Are you sure?
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3. Smells
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4. Economic smells
● Over 80% of time spent
reading code instead of
writing it.
● High maintenance cost.
● Unmotivated PEOPLE.
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5. Technical smells
● Classes with 2.000 lines of code
● Methods with over 200 lines of
code
● Lots of comments trying to
explain what the code is
supposed to do
● Duplicated lines of code (Copy &
Paste everywhere)
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6. Why do I have to take care of it?
Because you write it
Every time you write bad
code you are being part of
the problem
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7. Good Practices
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8. Intention-revealing names
Your classes, methods,
functions and attributes
should tell you why they are
there for
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9. Do what you are supposed to do
Each function, method or
class only has to contain the
business logic that they
declare
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10. Do what you are supposed to do
If you are writing an userand-password-checking
method, don’t start a new
session in the system, just
check if the user and
password are correct
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11. Don’t Repeat Yourself principle
Don’t clone code, reuse it
instead
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12. Don’t Repeat Yourself principle
Every time you copy & paste
code, you are exponentially
rising the probability of
having problems in your next
change
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13. Single responsibility principle
There should be only one
possible reason to modify a
class, method or whatever
artifact in your project
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14. Single responsibility principle
They need to have just ONE
RESPONSIBILITY each
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15. Small number of arguments
A small number of arguments
per method or function
indicates that we are...
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16. Small number of arguments
… sharing responsibilities
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17. Small number of arguments
… creating more reusable
data structures
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18. Small number of arguments
… decreasing the amount of
time spent on understanding
the purpose of this piece of
code
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19. Small artifacts
Small packages, classes,
methods, functions are a
signal of good code health
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20. Include comments in complex
algorithms only
This way we reduce the “I
have found comments that
say a different thing that
the code” risk
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21. Include comments in complex
algorithms only
Your code must be readable
and understandable by itself
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22. Tips to achieve this good
practices
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23. From Godzilla...
… to Puppet
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24. Set a maximum number of lines of
code
Limit the amount of allowed
code lines per class, method
and function
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25. Set a maximum number of lines of
code
I.E. A maximum of 10 lines
for methods and functions,
100 for classes
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26. Broken Phone
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27. Avoid comments
Every time you need to write
a comment, read the code
you have written again
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28. Work in pairs
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29. Invite people to read your code
Before commiting a line of
code, ask your partner for
reading it
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30. Invite people to read your code
Does he/she understand
what it is intended to do?
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31. Code is free
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32. Use more classes
If you need to write more
classes in order to reuse your
code, DO IT, THEY ARE
FREE!
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33. Now, do it
Lets start a refactoring
exercise to put in practices
this principles
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34. Now, do it
Is there any volunteer in the
room?
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