How to OOP helps to resolve and optimize JavaScript class dependencies(ajaxline.com)
submitted by 
luchkovsky(55) 4 years, 9 months ago
"Lazy inheritance" is a design pattern used in JavaScript computer programming. It designates a postponed linking of an object with it's prototype (class) until it is needed. If used properly, such approach may increase efficiency, simplicity and flexibility of OOP based code written using JavaScript.
Unlike of "classical" approach, it supports a "Lazy" way of
inheritance implementation, since reference to parent class is invoked only at the moment of object instance creation.
Basically, it's possible to say that instances of objects in such approach are created in "mixed" mode – on first invocation, an appropriate factory is used to modify object constructor prototype which is later used for subsequent object instances creation. Moreover, since "Lazy inheritance" is called only once at the moment
of first object instance creation, it becomes possible to combine process of class prototype creation with resolving necessary dependencies of that class. In other words, the process of prototype construction also allows loading scripts (if ones were not loaded before) which particular class depends on.
Such approach to inheritance support has the following benefits:
* "Lazy inheritance" has the same benefits as classical JavaScript prototype features;
* It is not necessary to maintain proper order of script files
declaration;
* In most cases, HTML page is loaded faster since there are no objects created during page initialization and since some scripts could be loaded only at the moment in which they are actually necessary (they are necessary if the caller code during it's execution really creates instances of corresponding classes);
* Dependencies are declared in more explicit way and class depends only on concrete scripts; Moreover, it's not necessary to artificially group particular scripts into "modules" and define dependencies between such "modules";
* If lazy mode of scripts loading is used, only necessary scripts (which are actually required for application functionality) will be loaded. If, for example, some HTML page may operate in different modes, like "read-write" and "read-only", for every mode required scripts will be loaded and this will be performed automatically without manual script loading optimization.
LINKS
http://ajaxline.com/node/367 - The article
http://sourceforge.net/projects/jsiner - The open source implementation read more...
|category: AJAX
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