mootools/mootools-core — comment on commit 6d949c693ccd11514f72ca01b72c59c25ec9de07
File: Source/Core/Core.js line 86
By ctumolosus:

i was wondering why not allow overloadSetter and overloadGetter pass any additional parameters? For examples, what if i wanted to call an overloaded method ::set(attributes, options) where attributes is a key value pair object with the actual keys and values that i would like set and options may be another object with options for the method. I thought it was useful and implemented my own by simply applying the additional arguments to the call.

var slice = Array.prototype.slice // in closure scope
...
self.apply(this, [ k, a[k] ].concat( slice.call(arguments, 1) ));

and when not usePlural

self.apply(this, [ a, b ].concat( slice.call(arguments, 2) ));