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![Simple Immutable
tweaks
arr.push(val) —> [].concat(arr, val)
obj[‘key’] = val —> Object.assign({key: val}, obj)
ImmutableObj = Object.freeze(obj)
** Object assign is limited to shallow cloning and
may produce strange outcomes.
see:
https:/
/developer.mozilla.org/en-US/docs/Web/
JavaScript/Reference/Global_Objects/Object/create](https://image.slidesharecdn.com/introtofunctionalprogramming2-170301075633-230706034620-ab8c518c/85/introtofunctionalprogramming2-170301075633-pdf-18-320.jpg)
introtofunctionalprogramming2-170301075633.pdf
- 1.
- 2. Why Do WeNeed to Change The Paradigm?! Object Oriented Programming is Awesome!
- 3. OOP is notcutting it
- 4. Testability Require lots ofmocking Extensive environmental setup Hard to maintain as the objects evolve
- 5. Complexity Tendency to over-design Re-Useis often complicated and requires frequent refactoring Often Objects DON’T represent the problem correctly
- 6. Concurrency Objects naturally livein a shared state environment Multiple Objects in a shared state environment handle concurrency poorly
- 7.
- 8. Why Functional?! Mathematical approachto solving problems More simple and less abstract Easy Reuse, Test and handle Concurrency
- 9.
- 10.
- 11. Pure Function Pure functionsact on their parameters Are not efficient if not returning anything Will always produce the same output for the given parameters Have NO side affects
- 12.
- 13.
- 14.
- 15. There are no“Variables” in Functional programming - all “variables” should be considered as constants
- 16. When Do wemutate variables? Short living “local” variables Loop flow structures State objects
- 17. Javascript is Nota pure functional programming language - it allows for mutable structures. We need to “tweak” it…
- 18. Simple Immutable tweaks arr.push(val) —>[].concat(arr, val) obj[‘key’] = val —> Object.assign({key: val}, obj) ImmutableObj = Object.freeze(obj) ** Object assign is limited to shallow cloning and may produce strange outcomes. see: https:/ /developer.mozilla.org/en-US/docs/Web/ JavaScript/Reference/Global_Objects/Object/create
- 19. For “real” projectsuse an immutable library such as ImmutableJS or seamless-immutable
- 20.
- 21. In Functional Programming,a function is a first-class citizen of the language. In other words: A function is just another value
- 22. Higher Order Functions Take functionsas parameters Return functions Both
- 25. A closure isa function’s scope that’s kept alive by a reference to that function.
- 26.
- 27. newFunc = f(g(x)) Applicationof one function to the result of another to produce a third function
- 29. A Problem Write acomposed function that does text Capitalization: “the FORCE is strong with YOU” —> “The Force Is Strong With You”
- 31.
- 33. Enhanced Capitalize Problem I wantto ignore a list of words: a, is, for, etc. so: “the FORCE is strong with YOU” —> “The Fore is Strong With You”
- 34.
- 35.
- 36. A Curried Functionis a function that only takes a single parameter at a time.
- 37.
- 38.
- 39. Map Creates a newarray with the results of calling a provided function on every element in the array
- 41. Filter Creates a newarray with all elements that pass the test implemented by the provided function
- 43. Reduce Applies a functionagainst an accumulator and each value of the array (from left-to-right) to reduce it to a single value
- 45. Summary Use “Pure” functionsto create predictable & stable code Use Immutable structs to avoid side effects Compose complex functionality from simple building blocks Use currying for simple composition Avoid “boilerplate” code and loops by using functional functions