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callAll with prototype method and child context


jensen
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Hello,

 

I am curious how people are handling the context for group.callAll when the method being called belongs to the prototype of the child.

 

Here is the situation I ran into. I'd love to see how people are handling a similar case in their usage of Phaser.

 

 

I have a Cell class that has a draw method. Something like this (code slimmed down for illustrative purposes).

Cell = function(game, x, y) {    Phaser.Graphics.call(this, game, x, y);}Cell.prototype = Object.create(Phaser.Graphics.prototype);Cell.prototype.constructor = Cell;Cell.prototype.draw = function(x, y) {    x = typeof x !== 'undefined' ? x : 0;    y = typeof y !== 'undefined' ? y : 0;    this.clear(); // Error occurs here, when this is a Boolean    this.beginFill(this.color);    this.drawRect(this.x + x, this.y + y, CELL_SIZE, CELL_SIZE);    this.endFill();}; 

I also have a group that I created to hold a number of cells. I want to call the draw method on each of them. I also want the context to be within the child so I use the value '' for the context parameter.

this.cellGroup.callAll('draw', '', x, y);

When I do this, I get an error:

Uncaught TypeError: Object [object Boolean] has no method 'clear' 

When I step through the callstack it is obvious why this error is occurring. Inside Group.js#callAll there is a check for context && callback. Since I have provided both it will attempt to determine the context using this.callbackFromArray. The issue I'm running into is that the contextLength is 1 because ''.split('.') is [''], but this.callbackFromArray returns false because it can't find child[callback[0]].

 

When false is returned it tries to call clear on the boolean and results in the error. I am able to leave my code unchanged by making this change in Group.js#callAll.

else{    var contextLength = 0;    //  Extract the context into an array    if (typeof context === 'string' && context != '')    {        context = context.split('.');        contextLength = context.length;    }}

I would love to chalk this up to my inadequate understanding of the JavaScript language. Please advise.

 

Thanks,

Karl

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I actually updated Group.callAll tonight to cope better with this. It's in the 1.2 branch but essentially all I did was this:

    if (typeof context === 'undefined' || context === null || context === '')    {        context = null;    }    else    {        //  Extract the context into an array        if (typeof context === 'string')        {            context = context.split('.');            var contextLength = context.length;        }    }

So you can pass null or '' as the context now and it won't try and split it.

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