How can I inherit an objects variables within namespace(scope)?
var f2 = {
a: 'test'
}
f2.history = {
load: function(){ alert(this.a); }
}
// Turns out Undefined
f2.history.load();
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2 Answers
There is no link between f2.history and f2. More generally there is no link between a property value and its holder.
You could call it like this :
f2.history.load.call(f2);
Or you could declare your objects with a factory :
var f2 = (function(){
var self = {
a: 'test'
};
self.history = {
load: function(){ alert(self.a); }
};
return self;
})();
This would allow
f2.history.load();
Another variant would let you define the submodules in a more separated way :
var f2 = {
a: 'test'
};
(function(f){
f.history = {
load: function(){ alert(f.a); }
}
})(f2);
The advantage of this last construct is that it's easy to declare sub-modules in different files.
3 Comments
Adrian McCool
Seams really complicated, could I just use the prototype chain somehow?
Bergi
@AdrianMcCool: You could make
f2.history inherit from f2, but that hardly makes any sense to me
Denys Séguret
Modules/submodules and inheritance are very different concepts. Inheritances makes little sense without instantiation.
use the namespace, f2, not this.
load: function(){ alert(f2.a); }
works
var f2 = {
a : 'test',
init: function(a) {
if (a) this.a = a; //set a, if a is defined
},
};
function history(a) {
function F() {};
F.prototype = f2;
var f = new F();
f.init(a);
load = function() {
alert(f.a);
}
return this;
}
var h1 = history();
h1.load(); //alerts "test"
var h2 = history('history');
h2.load(); //alerts "history"
//but now h1 also holds history
h1.load();
1 Comment
davidkonrad
OK. But why would you want to "override" an object literal? There is only one f2 (example)