http://brendaneich.com/2011/10/jsconf-eu/
I’d be sad not to have class literals in JavaScript. However, with the new
object literal extensions, things are still much better than in ES5. Compare:
The ES5 version is clumsy.
// Super
function Person(name) {
this.name = name;
}
Person.prototype.describe = function() {
return "Person called "+this.name;
};
// Sub
function Employee(name, title) {
Person.call(this, name);
this.title = title;
}
Employee.prototype = Object.create(Person.prototype);
Employee.prototype.constructor = Employee;
Employee.prototype.describe = function() {
return Person.prototype.describe.call(this)+" ("+this.title+")";
};
The ES.next version is quite nice:
// Super
function Person(name) {
this.name = name;
}
Person.prototype .= {
describe() {
return "Person called "+this.name;
}
}
// Sub
Person <| function Employee(name, title) {
super(name);
this.title = title;
}
Employee.prototype .= {
describe() {
return super.describe(this)+" ("+this.title+")";
}
};
This is not bad at all, quite teachable! Having a single construct instead of
piecing things together via multiple assignments might be a problem in some
cases. Then you could use the latest incarnation of Allen’s class pattern:
Person <| function Employee(name, title) {
super(name);
this.title = title;
}.={
prototype.={
describe() {
return super.describe(this)+" ("+this.title+")";
}
}
// “class” variables go here
}
[I’m using the destructive version of the extension operator, as shown in
Brendan’s blog post]
--
Dr. Axel Rauschmayer
a...@rauschma.de
home: rauschma.de
twitter: twitter.com/rauschma
blog: 2ality.com
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