Introduction to functional programming with JavaScript
- 1. Introduction to Functional Programming with JavaScript
- 2. Introduction Farzaneh Orak Software Engineer Hunter Industries Mob programming
- 3. Goal
- 4. FP and OOP Object-Oriented ProgrammingFunctional Programming
- 5. JavaScript language • Multi-paradigm • First class function
- 6. Which one is better? • Depend on what are you trying to do • Michael Fogus author of “Functional Javascript” • Deal with data about people -> FP • Simulate people -> Object-Oriented Programming
- 7. When we use functional • People simulation • Shared state • Data about people • Avoid shared state
- 8. What is Functional programming? • Programming paradigm • Style-organizing coding • Way of thinking • Express everything in term of functions • Declarative
- 9. Why functional programming? • Increase readability and maintainability • Function reusability • Easier testing and debug • Needs low brain power to read the code
- 10. Why functional programming? • Elegant code • Predictability • Less complex
- 11. Functional Programming principles • Avoid sharing state • Avoid side effect • Avoid data mutation
- 13. Avoid side effect • Console log • Writing to a file
- 14. Avoid data mutation • Once object created it can’t be changed
- 15. Functional Programming Techniques • Pure function • Higher order function
- 16. Functional Programming principles • Pure functions • Given the same input, It always returns the same output
- 17. Impure vs Pure functions
- 18. Pure functional- Avoid sharing state
- 19. Pure functional- Avoid side effect
- 20. Functional Programming Techniques • Higher order function • Function composition • Functions re-usability • Function currying
- 21. Functional Programming Techniques • Higher order functions • Pass functions as arguments or return functions
- 25. Higher order functions • Map • Filter • Reduce
- 26. Map • Avoid data mutation
- 27. Map example
- 28. Reduce • Higher order function • Works on variety of datatype
- 29. Reduce
- 30. Filter • Avoid data mutation
- 34. Trie data structure • Trie data structure • Structural sharing
- 35. Trie data structure 6 242 64 5
- 36. Libraries • JFP • Ramda • Lodashfp • Mori • Immutable js
- 37. Recap • Functional Programming Principles • Avoid shared state • Avoid side affect • Avoid data mutation • Functional Programming Techniques • Pure function • Higher order functions