Higher Order Functions

Higher Order Functions

"In mathematics and computer science, a higher-order function (also functional, functional form or functor) is a function that does at least one of the following: takes one or more functions as arguments (i.e., procedural parameters), returns a function as its result." Wikipedia

In this example we manipulate the array:
[2,4,8,9,11,13]

By using the Higher Order function "map" inside the Array object, we can pass a function to manipulate each item in the array.

First we initialize and output the array:
var a = [2,4,8,9,11,13]; console.log(a);

And Declare a custom Higher Order Function:
Note: This uses ES6 format.function mult(multiplier){return x=>x*multiplier;}

The JS Array Object has internal functions.
We will be using the "map" method
(A Higher Order Function)
Which expects a function as the parameter and returns a new processed array.

Now we can call Array.map and pass our own Higher Order Function "mult" (giving value 2 as param) which returns an anonymous function to map thus multiplying each index by 2:
var b = a.map(mult(2)); console.log(b);

Next we will store the anonymous function returned from "mult(3)" in the variable "trip":
var trip = mult(3);

Lastly we use the stored function with map to get an array with each index multiplied by 3:
var c = a.map(trip); console.log(c);

By: Michael Simnitt

Higher Order JS