Searching and Sorting Without Loops

At the recent San Francisco JavaScript meetup, I gave a talk on the subject of Searching and Sorting without Loops as part of its Functional Monthly series. In that talk, I explained various higher-order functions of JavaScript Array and their usage to replace explicit loops (for or while) in several different code patterns.

I have published the slide deck for the talk (as PDF, 1.4 MB). The talk started with a quick refresh of five Array’s functions: map, filter, reduce, some, and every. Those functions will be used in the subsequent three parts of the talk: sequences, searching, and finally sorting. The first one, building sequences without any explicit loop, sets the stage for the rest of the discussion.

If you are following this blog corner, you may notice that this is not a new topic. This talk is basically a detailed walkthrough of some posts I have written in the past:

• Sequences using JavaScript Array
• Prime Numbers, Factorial, and Fibonacci Series
• Searching: Array.prototype.some vs Array.prototype.reduce
• Sorting Networks using Higher-Order Functions

It seems that you will need a lot of effort to understand all this complicate stuff. Nevertheless, think about the reward. Being able to understand this code fragment (fits in a single tweet) that constructs the first n numbers in the Fibonacci series is quite satisfying:

function fibo(n) {
  return Array.apply(undefined, Array(n)).
    reduce(function(x, y, z){ return x.concat((z < 2) ? z : x[z-1] + x[z-2]); }, []);
}

The age of exploration is just beginning.