Is writing code chronologically the best way for readability?

Question

So I've been writing a lot of JavaScript lately. Despite what many people say I think JavaScript can be a simple and beautiful language.

What I've pondered of late is how to structure the code so it is best readable to the human eye.

Sometimes there are cases like this:

mainFunction = function(){
  var init = function(){
    // do some initialization
    doSomeThing();
    doAnotherThing();
    window.addEventListener("scroll", someCallback);
  }
  var someCallback = function() {}
  var doSomeThing = function() {
    // code
  }

  var doAnotherThing = function() {
    // code
  }

  init();
}

You first have to define all functions before you can initialize some thing and finally do the stuff you wanted to do.

Now when I'm reading code, I always try to read it in a chronological order first, that's just how my brain works. But with JavaScript, the longer the code gets, the more complex I find to see where the start point is.

So I guess my questions are:

Are most people reading code chronologically? Is chronological the best way for readability?
How to achieve this in JavaScript? (What are some languages that do it better)
What are some common JavaScript code writing philosophies out there?

possible duplicate of [Are there any OO-principles that are practically applicable for Javascript?](http://programmers.stackexchange.com/questions/180585/are-there-any-oo-principles-that-are-practically-applicable-for-javascript) — gnat, Jul 21 '15 at 10:35
The longer the code gets, the more difficult it becomes to read. Ergo, don't write long code. — David Arno, Jul 21 '15 at 10:37
`You first have to define all functions before you can initialize some thing and finally do the stuff you wanted to do.` - you don't have to, if you use the function declaration statement. i think it's cleaner, to see what gets called first, and the definition below. so yes, i think chronological order is often a good choice — Bruno Schäpper, Jul 21 '15 at 10:42
Personally, I like to avoid "inner functions" like this, instead defining all functions at the "top level" of the module, unless they're tiny one-off callbacks to sort()/filter()/map()/etc. The body of any single function should not be long enough to make it hard to scan (in any language) imo. But this question is a broad opinion poll which doesn't work that well on this site so it'll probably get closed. — Ixrec, Jul 21 '15 at 11:00

score 3 · Answer 1 · answered Jul 21 '15 at 14:32

If putting the functions chronologically improves the readability of the code, it means that you are using functions wrong. The primary purpose of dividing the code to function is to reduce the amount of context you need to hold in your mind at any given time.

(functions have other usages when you use recursion or higher-order functions, but that's clearly not the case in your example(maybe except someCallback))

"The competent programmer is fully aware of the strictly limited size of his own skull; therefore he approaches the programming task in full humility, and among other things he avoids clever tricks like the plague."
Dijkstra (1972) The Humble Programmer (EWD340).

You break the big code into smaller functions so you can look at each function on it's own, and only have to think of what one function does at any given moment. Even with functions that call other functions(like the mainFunction) you don't think about what each of these functions does, instead abstracting them to atomic commands. This means you don't have to look at the entire flow of the program as a whole - so it doesn't matter if the functions are ordered according to that flow.

Is writing code chronologically the best way for readability?

1 Answers1