Functional Programming with JavaScript

Functional Programming with JavaScript

• 1.
  Functional Programming With JavaScript
• 2.
  In the beginning,God created “Programming paradigms” in 7 days (Genesis 101)👼 Imperative Programming Procedure Programming Object Oriented Programming Functional Programming ~ a coding style / a way of thinking
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  တူတတောော်တ ောငော်တ ို့
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  တ ေးတေတောပဲ ဘောထူေးလို့လဲ Q: Don’t we write functions in every language ? A: But functional programming take it to a whole another level Def : Break any complex problem down into smaller sub-problems, solve them using functions, and finally combine them together to solve the bigger problem.
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  ဘယော်သူတတွေသေးလ ို့လဲ F#, C#(.NETs) Lisp & Perl (grandpas) Erlang , Elixir & Haskell (hotshots) Clojure & Scala (JVMs) D, R, JS, Python, … (sexies)
• 6.
  Why FP inJavaScript The root of all evil is “this” keyword 😈 Object.prototype OOP in JS is like sugar coated paracetamol 💊 .call .apply .bind // anyone ?
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  Input => process=> output f(x) = x * x // function (x) { return x * x } g(f(x)) “ Programmer think of their programs more as pipes for data to travel through just like we did in Math “ Source ~ wellesley.edu
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  Imperative let name =“azb” let greeting = “Hello, I’m ” console.log(greeting + name) function greeting(name){ return “Hello, I’m ” + name } greeting(“azb”) Functional
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  First-class citizen အခွေငော်ို့ထူေးခလူတေော်ေးစောေး Treat like other values Pass around arguments and return as value Define and manipulate functions from other functions Reference from variable or self
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  Side Effects Changing thevalue of a variable (parent/ global), OBVIOUSLY Writing some data to disk, file, console, network Manipulating of UI Calling external process Generally - STATE CHANGED
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  Pure functions (noside effects)
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  High-order function (return)
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  High-order function (accept)
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  Referential transparency function add(a,b) { return a + b } add(add(2, 3), add(4, 1)) add((2 + 3), add(4, 1)) add((2 + 3), (4 + 1)) (2 + 3) + (4 + 1)
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  Don’t LOOP (streamof data / HO funs) .forEach .map .reduce .filter
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  Immutability is bad .pop.push .shift .unshift let a = 1 a = “hello world”
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  Persistent data structures var,let, const right ? ahuh not really Wait a min Object.freeze Object.seal MORI IMMUTABLE (sponsored by facebook) Underscore Lodash Ramda
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  More FP Currying Tail Recursion Patternmatching Infinite data structure Composition Lazy evaluation self.Q&A Concurrency Parallelism Async
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  READABLE, EASY TOUNDERSTAND, REUSABLE Writing with a larger team Application larger than a todo app Performance are not critical You have to support the project P.S 1. I/O is tricky in FP 2. Code LineNums are just a number 3. There’s no single true paradigm
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  Aung Zan Baw- တအောငော်ဇတဘောော် Web developer (Fairway Technology)
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  Links Slides - https://goo.gl/3fmMXk BestFP in JS - https://goo.gl/IqmkoT ReactiveX !!! Starter book - https://goo.gl/ctmBTo