It can be challenging to determine which option is superior based on the specific context in which they are utilized.
When deciding between coding methods like Prototype and Closure, I consider three key factors (given that I actively employ both):
- Performance/Resources
- Compression requirements
- Project Management
1. Performance/Resources
If I only need a single instance of the object, either method works adequately with negligible speed differences. However, if I have to create 100,000 instances (e.g., for a book library), the Prototype Method is more efficient. This is because all .prototype functions are created just once, unlike the Closure Method where they would be replicated 100,000 times. Resources are precious and not unlimited.
2. Compression
For situations where compression efficiency matters (such as browser libraries/modules), I opt for the Closure Method. Here's why:
Compression - Prototype Method
function Book(title) {
this.title = title;
}
Book.prototype.getTitle = function () {
return this.title;
};
After compression, YUI reduces it to
function Book(a){this.title=a}Book.prototype.getTitle=function(){return this.title};
This results in approximately an 18% reduction (excluding spaces/tabs/returns). However, variables/functions must be exposed using "this.variable=value," limiting optimization potential during compression.
Compression - Closure Method
function Book(title) {
var title = title;
this.getTitle = function () {
return title;
};
}
After compression, YUI reduces it to
function Book(a){var a=a;this.getTitle=function(){return a}};
This approach achieves around a 33% decrease in size. Local variables can be optimized, offering significant compression savings particularly in larger modules with numerous support functions.
3. Project Management
In collaborative projects involving multiple developers working on the same module, I prefer utilizing the Prototype Method, unless performance or compression concerns dictate otherwise.
When developing for browsers, I can override "production.prototype.aFunction" from "production.js" with my own "test.js" (loaded afterward) for testing purposes without modifying the actively developed "production.js."
I tend to avoid complex GIT repository workflows involving checkout, branching, merging, and conflicts, opting for simplicity.
The ability to redefine or "hijack" a module's function for testing purposes can indeed be advantageous, but delving into the complexities of this process is beyond the scope of this discussion...