Forums » Help » Finding an Impact Object's Name or Type

In collideWith() or check() it would be helpful to know the Object type or name of the other parameter. I'd rather not have to loop through a switch() of instanceof's for all Entity types I have defined. Any ideas?

Let's say a bomb entity is checking against a glider entity. You can simply give EntityGlider a name property as in:

name: "glider",
...

Then in the check function of the bomb, just see if the name matches:

if (other.name == "glider"){
  //There is a match so do whatever needs to be done here
}

@MikeL -> can we assign the name via Weltmeister? (i.e we select the entity via a mouse click, and add the "name" property )

@fugufish: yes, you can assign the name property in WM.

Back to the original topic: what would be the benefit of

if( other.name == "glider" ) { ... }

over

if( other instanceof EntityGlider ) { ... }

?

Well the original statement was phrased "it would be helpful to know the Object type or name of the other parameter". Which I took to mean "how can I introspectively retrieve the name or type of the entity?"

I can't for example do something like:

alert('instance ' + EntityGlider.instance);

so far as I know, to directly retrieve the string value of the EntityGlider name. You can check if it&039;s an #instanceof which is probably suitable for most cases as you are indicating. I came across this issue when I was trying to get the string value of javascript object names and that was the only workaround I could find.

But is there another way?

Well, there's no way in JavaScript to get the name of a class (or property for that matter) directly, without having the name stored as a string somewhere. The reason is quite simply that there's no unambiguous "name" for anything:

FooClass = ig.Class.extend({});
BarClass = FooClass;

foo = new FooClass();
foo instanceof FooClass; // true
foo instanceof BarClass; // true

// fictional:
foo.getClassName(); // Which one is it? 'FooClass' or 'BarClass'?

But you could overwrite the spawnEntity() method in your game class (untested):

spawnEntity: function( type, x, y, settings ) {
	var ent = this.parent( type, x, y, settings );
	ent.className = typeof(type) === 'string'
		? type
		: 'unknown';
		
	return ent;
},

After that, all entities will have a .className property. However, you have to restrict yourself to always call spawEntity() with the class name as string, instead of with the class itself. E.g.:

var g1 = ig.game.spawnEntity( 'EntityGlider', x, y );
g1.className; // EntityGlider

var g2 = ig.game.spawnEntity( EntityGlider, x, y );
g2.className; // unknown

Ah, ok thanks for clearing that up. That's very useful info.