Is the capability to overwrite functions in JavaScript strength or weakness?
- by S.N
I recently came across the following code (from liferay.js) when I was working with Liferay:
....
if (!Liferay._ajaxOld) {
Liferay._ajaxOld = jQuery.ajax;
}
if (Liferay._ajaxOld) {
jQuery.ajax = function(options) {
if (Liferay.Util) {
options.url = Liferay.Util.getURLWithSessionId(options.url);
}
return Liferay._ajaxOld(options);
};
}
....
As you can see, the code above overwrites the function "jQuery.ajax" to modify "options.url". One may say this is a strength of the language since we can easily overwrite and customize existing functions.
However, I would imagine this capability can easily lead to a problem. For instance, my code can overwrite the same function "jQuery.ajax" to modify "options.url" differently from the code above. As a result, any code that expect the behavior defined by "liferay.js" may no longer function as expected.
I see this as a weakness of the language as it does not provide proper encapsulation.
What are the consensus about this feature/capability of the language in the field?
