My function gets model name as string, I need to create new instance of object based on its name.
ex.:
modelName = 'MockA';
model = new modelName();
this is ofcourse not working. in php i would use
model = new $$modelName
thanks in advance
If MockA is in global scope you can use:
var model = new window[modelName]();
if not then you should reconsider the way you store your models, eg. with an object of models:
var my_models = {
MockA: function() {},
MockB: function() {}
}
and to access
var MockA = my_models.MockA;
// or
var model_name = 'MockA';
var MockA = my_models[model_name];
You can use an object factory or bracket notation.
Sample of code:
// First example: Use a Factory
var MockA = function() {
this.sayHello = function() {
console.log('Hi from MockA ');
};
},
MockB = function() {
this.sayHello = function() {
console.log('Hi from MockB ');
}
},
factory = function(type) {
var obj;
switch (type) {
case 'MockA':
obj = new MockA();
break;
case 'MockB':
obj = new MockB();
break;
}
return obj;
}
var objA = factory('MockA');
objA.sayHello();
var objB = factory('MockB');
objB.sayHello();
// Second example: Using bracket notation
var models = {
BaseMockA: {
sayHello: function() {
console.log('Hi from BaseMockA ');
}
},
BaseMockB: {
sayHello: function() {
console.log('Hi from BaseMockB ');
}
}
};
var baseObjA = Object.create(models['BaseMockA']);
baseObjA.sayHello();
var baseObjB = Object.create(models['BaseMockB']);
baseObjB.sayHello();
Related
I am trying to figure out how to put an object to a function and return that
object with its original values.
It's part from my "framework"...
Here an simplified example:
var _objectToFunction = function (obj) {
var F = function () { }
F.prototype = obj
return F
}
var myclass = {
a:"abc",
print: function(){
console.log("i am a func")
},
config: {
path: "c:/bla"
}
}
var fo = _objectToFunction(myclass)
var of = new fo()
of.config.path = "c:/ofpath"
of.z = "zzz"
of.a ="aaa"
console.log(of)
var fo2 = _objectToFunction(myclass)
var of2 = new fo2()
console.log(of2.z)
console.log(of2.a)
console.log(of2.config.path)
The output from console.log(of2.config.path) should "c:/bla", but is "c:/ofpath".
How can I do this right?
You may want to add a constructor (a function that is called, when an instance was created):
var _objectToFunction = function (obj) {
var F = function (...values) {
if( this.constructor) this.constructor(...values);
}
F.prototype = obj
return F
}
So you can create a new config Object for each instance:
var myclass = {
constructor:function(addconf){
this.config=Object.create(this.config);
if(addconf) Object.assign(this.config,addconf);
},
a:"abc",
print: function(){
console.log("i am a func")
},
config: {
path: "c:/bla"
}
}
Now it behaves as wanted.
var parent=_objectToFunction(myclass);
var instance=new parent({ path:"changed"});
Or with standard object funcs:
var instance=Object.create(myclass);
instance.constructor({path:"changed"});
I am just learning javascript and I need to know how I will go about doing this please:
Task: Merge the given objects into var C
var a = {
name: "Danny"
};
var b = {
getName: function () {
return this.name;
}
};
Output should be danny
var solve = function () {
var C;
var instance = new C();
console.log("Name: "+ instance.getName());
};
solve();
You can use Object.assign() to merge existing objects into any other object. The syntax is:
Object.assign(target, src1, src2, ....);
And, here it is working with your code:
var a = {
name: "Danny"
};
var b = {
getName: function () {
return this.name;
}
};
var C = function() {
Object.assign(this, a, b);
}
var instance = new C();
console.log("Name: "+ instance.getName());
I found a Module pattern in JS:
<script>
var MODULENAME = (function(my, $) {
my.publicVar = "5";
my.publicFn = function() {};
return my;
}(MODULENAME || {}, jQuery));
</script>
However I cannot perform instantiation. Does the module pattern allow for that?
Instantiantion means basically that you'll run a function using new.
So maybe you're looking for this?
var Some = function (param) {
var somePrivateVar = 'private';
this.somePublicVar = 'public';
this.method = function () {
return param;
};
};
var some = new Some('abla');
console.log(some.method());
// some.somePrivateVar === undefined
// some.somePublicVar === 'public'
In your case MODULENAME is an object (object, not a function) with publicVar and publicFn. It's not meant to be instantiated the same way you wouldn't call new jQuery().
Your module object can contain anything. Perhaps you're looking for including a constructor in it:
var MODULENAME = (function(my, $) {
var privateVar = 10;
my.SomeConstructor = function() {
this.publicVar = 5;
}
my.SomeConstructor.prototype.someMethod = function() {};
my.SomeConstructor.prototype.getPrivate = function() { return 10; };
return my;
}(MODULENAME || {}, jQuery));
var instance = new MODULENAME.SomeConstructor();
instance.publicVar; // 5
instance.privateVar; // undefined
instance.getPrivate(); // 10
You can do this also with prototype Inheritance :
var MyClass = function(name)
{
//sharing name within the whole class
this.name = name;
}
MyClass.prototype.getName = function(){
return this.name;//now name is visible to getName method too
}
MyClass.StaticMethod = function()
{
console.log("Im Static");
// and since is not in prototype chain, this.name is not visible
}
var myclass = new MyClass("Carlos");
console.log(myclass.getName())//print "Carlos"
MyClass.StaticMethod()// print "Im Static"
myclass.StaticMethod() // error
Se all this article
I have a Constructor function "Animals", that is namespacing some other Constructor functions, "Crocodile" and "Monkey":
var Monkey = function(Animals) {
this.Animals = Animals;
};
Monkey.prototype.feedMe = function() {
this.Animals.feed();
};
var Crocodile = function(Animals) {
this.Animals = Animals;
};
Crocodile.prototype.feedMe = function() {
this.Animals.feed();
};
var Animals = function(zoo) {
this.zoo = zoo;
};
Animals.prototype.feed = function() {
//feed the animal
};
Animals.prototype.Monkey = function() {
this.Animals = Animals.prototype;
};
Animals.prototype.Monkey.prototype = Monkey.prototype;
Animals.prototype.Crocodile = function() {
this.Animals = Animals.prototype;
};
Animals.prototype.Crocodile.prototype = Crocodile.prototype;
With the intention that I should be able to do the following:
var animals = new Animals("NY");
var monkey = new animals.Monkey();
monkey.feed();
I'm receiving an error that says that monkey.feed() is not a function. I'm assuming i'm doing something wrong with the way i'm inheriting the Monkey function inside the Animal constructor function but for the life of me I haven't been able to find the solution.
What is the correct method I should be using to namespace these functions?
I have seen quite some stuff, but abusing prototypes for namespaces, what the heck. What's wrong with a nice and simple:
var Animals = {
Crocodile: {
}
}
Or if you want the constructor way:
var Animals = function () {
return {
Crocodile: function () {}
}
};
var a = new Animals();
var c = new a.Crocodile();
I have JavaScript variable as a literal:
var global = {
getTime : function() {
var currentDate = new Date();
return currentDate.getTime();
}
};
And I wish to extend this literals with other different functions, which are going to be created as variables:
var doSomething = function(param){
$("#" + param).hide();
return "hidden";
}
How can I extend my literal with a new variable, which holds a function?!At the end I wish to use this in such a way:
alert( global.doSomething("element_id") );
To extend your global variable with the method doSomething, you should just do this:
global.doSomething = doSomething;
http://jsfiddle.net/nslr/nADQW/
var global = {
dothis: function() {
alert('this');
}
}
var that = function() {
alert('that');
};
var global2 = {
doSomething: that
};
$.extend(global, global2);
$('#test').click(function() {
global.doSomething();
});
global.doSomething = function(param){
or
var doSomething = function(param){ ...
global.doSomething = doSomething;