Question

I’m writing a JavaScript plugin that receives a set of settings, some required, some not. It’s actually a plugin for Raphael.js but this question extends to jQuery plugins too.

My code looks something like the following:

jQuery.fn.myplugin = function (settings) { 
    settings = settings || {};
    var reqParam1= settings.requiredParameter1 || return; //Or throw? //Or ... ?

    /* More code */
}

If I determine that the plugin didn’t receive all the required settings, what course of action should I take? The obvious and most conservative choice is to throw but what about in the case where the plugin functioning isn’t ‘essential’? By not ‘essential’ I mean purely an aesthetic enhancement or less-than-critical to the rest of the page. In this case could it be correct to die silently?

Answer 1

You should throw on mandatory parameters, if it means your plugin cannot function (but try to keep mandatory parameters to a minimum), and use defaults for everything else.

jQuery.fn.myplugin = function (settings) { 
    settings = $.extend({}, $.fn.myplugin.defaults, settings);
    if(!settings.requiredParameter1) throw "Missing requiredParameter1";

    /* More code */
}

jQuery.fn.myplugin.defaults = {
  optionalParameter1: true
}