How do you work with long variables in Javascript?

Question

Hi,

How do you recommend to work with long variables in Javascript? Thanks!

For example...

window.location.hash.substring(2).split("/")[0].something().hello;

object["object"].object(object.hello.how.are.you[another.object(function.inisde())]);

My solutions

• Use with() { (...) }

Answer 1

If you're going to be using it more than once, definitely assign it to another variable

var simple = object.hello.how.are.you[another.object(function.inisde())];

Answer 2

I find it useful (in any language) to NOT chain method calls together in most cases. The cons to doing this are

1) If there is some sort of null exception, it is difficult to know where it occurs, especially if the code looks like

if (a.b.c.d.e || f.g.h.i.k) { ... }

then your NPE like exception could have happened in any of 10 places. Imagine if the variables are more than 1 letter long.

2) The code is less readable this way. The following is infinitely more readable.

var b = a.b,
    c = b.c,
    d = c.d,
    e = d.e;
var conditionOne = e.isTrue()

you don't necessarily need to create a var for every level, but you could for levels that make sense.

3) Its easier to see what is going on in a debugger if the variables are separated out.

The bottom line is, with some extra typing your code is a lot more readable and a lot more maintainable.

Answer 3

If you have to use expressions like

object["object"].object(object.hello.how.are.you[another.object(function.inisde())]);

it usually means code is badly designed. :) The usual method to make this code comprehensible is to use variables. It requires more code, but at least it becomes readable.

var anotherObject = another.object(function.inisde())
var hello = object.hello.how.are.you[anotherObject];
object["object"].object(hello);

If the expression is linear, you can easily split it into several lines.

window.location.hash.substring(2)
    .split("/")[0]
    .something().hello;