Introduction to Functional Programming youtube videos

An introduction to functional programming

Functional programming on JavaScript

• Higher-order functions: functions that take functions as arguments. Functions are like variables too. Examples:
  • Filter
  • map: Transforms arrays
  • Reduce: iterates through objects in array, with an accumulator. Accumulator can be any data type, including objects. See MDN reference too.
  • Closures. Functions can access variables outside its scope
  • Currying. Decompose a function so that you first call it with an argument that returns a function, which you then call with second argument, etc. Basic usage. Can use lodash to curry existing functions, see an example of using lodash
  • Recursion is when a function calls itself, until it doesn't.
  • Promises. Like callbacks but more powerful as they are composable. Example
• Functors. Objects that hold collections of objects (like arrays) that have the map() function so that one can map these collections to other collections of the same size. One can made the analogy more precise between these and functors in Category theory which is very related to functional programming ideas.
• Monoids.

Nice game to explain map, reduce, filter: http://david-peter.de/cube-composer/

Functional programming languages

Clojure

The syntax is so nice. As he says in the vid, there is basically no syntax. It also reminds me of the data structures used for CASs

Lisp

Scala. yt vids

Scheme

Haskell. http://learnyouahaskell.com/