The document discusses various refactoring techniques for TypeScript, React, Next.js, and Nest.js projects. It recommends avoiding enums and long switch statements, extracting types from objects, using union types instead of multiple fields in an interface, different rendering strategies in Next.js like static site generation and incremental regeneration, and best practices like excluding unneeded fields and database seeding in Nest.js.

1. REFACTORING
TYPESCRIPT

2. DON’T USE ENUM
• Enums generate additional
code at compile time, which
increases the size of the final
file.
• Regular numeric enums are not
type safe
Before After

3. DON’T USE ENUM
• Use object or literal union type
instead.
Union Type Object

4. LONG SWITCH STATEMENT
• Avoid using long switch statement.

5. LONG SWITCH STATEMENT
• Avoid using long switch statement.
• Try to replace with object.

6. AVOID USING EXPLICIT TYPE
• Don't declare a type more than
once if it depends on an object.

7. AVOID USING EXPLICIT TYPE
• Analyze the dependant object to
try and extract the type.

8. AVOID USING EXPLICIT TYPE
• Don't declare a type more than
once if it depends on an object.

9. AVOID USING EXPLICIT TYPE
• If the type is derived from an
array, try to extract it using the key
"number."

10. AVOID USING EXPLICIT TYPE
• Extraction of the type from the
array item type is another option.

11. FUNCTION OVERLOADING
• function overloading produces the
proper return type.

12. FUNCTION OVERLOADING
• function overloading produces the
proper return type.

13. REFACTORING
REACT

14. COMPONENTPROPSWITHOUTREF
• Use "ComponentPropsWithoutRef"
instead of specifying the HTML tag
type.
My
Button

15. COMPONENTPROPSWITHOUTREF
• Use "ComponentPropsWithoutRef"
instead of specifying the HTML tag
type.

16. UNION TYPE
• The same interface should not
contain several fields together.
Attempt to separate it using a
union type.

17. UNION TYPE
• The same interface should not
contain several fields together.
Attempt to separate it using a
union type.

18. REFACTORING
NEXT.JS

19. CLIENT-SIDE RENDERING
API

20. SERVER-SIDE RENDERING
API
/articles/ts-5

21. STATIC-SITE GENERATION
/articles/ts-5
js.html
ts-5.html

22. INCREMENTAL STATIC REGENERATION
/blog
blog.html
regenerate

23. STANDALONE BUILD
next.config.js

24. STANDALONE BUILD
Dockerfile

25. REFACTORING
NEST.JS

26. USE EXCLUDE ALL STRATEGY

27. USE EXCLUDE ALL STRATEGY
main.ts

28. PICK ONLY THE
FIELDS YOU INTEND
TO BENEFIT FROM.

29. DATABASE SEEDING
tsx prisma/seed.ts

30. CONFIGURATION MANAGEMENT