Skip to content

Latest commit

 

History

History
14 lines (10 loc) · 1.23 KB

readme.md

File metadata and controls

14 lines (10 loc) · 1.23 KB

Flying first-class with higher-order functions

We say a language has "first-class functions" if it supports functions being passed as input or output values of other functions. JS has this feature, and JavaScripters take advantage of it all the time - e.g. it's what allows us to pass a callback function as an input parameter for another function. It's also possible to have a function as a return value. A function which either takes or returns another function is called a "higher-order function".

Exercises

Filter, Map, Reduce (filterMapReduce.js)

  • Run the tests in filterMapReduce.test.js with the command node filterMapReduce.test.js - tests should be failing
  • Work through the TODOs in filterMapReduce.js to write recursive implementations of all three functions
    • To move away from the object-oriented method-calling mindset to a functional mindset, use the helper functions head, tail, and count defined in arrayHelpers.js
    • Run the tests again - most should now be passing
  • Work through the TODOs in filterMapReduce.test.js to write applications of these functions that get the remaining tests to pass
  • Compare your implementations with those of your partner/group and discuss