defaults

Default values can be set on parameters as fallback values on initialisation.

A default can be set from either a value to be substituted or you can pass a function to be executed on instantiation.

class Foo extends MooseJS.defineClass({
    final:true,
    has:{
        classCreated:  { is:"ro", isa:Date, required:true, default:new Date() }, // From value
        objectCreated: { is:"ro", isa:Date, required:true, default:() => new Date() }, // From function
    },
})
{}

When defaulting to a function value you may have to wrap the function itself in an arbitrary wrapper function to stop MooseJS from interpreting it as a function to be executed.

class Bar extends MooseJS.defineClass({
    final:true,
    has: {
        onload: { is:"rw", isa:Function, required:true, default:() => function(){ console.log("I'm the default") } }
    }
})
{};