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POjavascript type issue: Uncaught TypeError: Object 0 has no method 'draw'
 

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  1. POjavascript type issue: Uncaught TypeError: Object 0 has no method 'draw'
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    <p>Just experimenting with JS + canvas and i seem to have hit a wall. the "aim" of my minimal application is to click at any random place on the canvas, press the draw button and squares draw where you clicked.</p> <p>coming from an OO background... i (tried) to use OO, which in js i dont fully have the grasp of. </p> <p>but basically i have a custom Square object</p> <pre><code>function Square(l, w, x, y) { this.length = l; this.width = w; this.posx = x - l/2; this.posy = y - w/2; //test //ctx.fillStyle = "rgb(20,0,0)"; //ctx.fillRect(this.posx,this.posy,this.length,this.width); this.draw = function() { ctx.fillStyle = "rgb(20,0,0)"; ctx.fillRect(this.posx,this.posy,this.length,this.width); } } </code></pre> <p>which i add to an array every time the user clicks... here is the event handler for when i click on the canvas.</p> <pre><code>function addTo(evt) { pos = getMousePos(evt); var sq = new Square(50, 50, pos.x, pos.y); list.push(sq); output.innerText = "("+sq.posx+","+sq.posy+")"; } </code></pre> <p>and here is where i (attempt) to draw the squares.</p> <pre><code>function renderStack() { //alert(list); canvas.width = canvas.width; for(var o in list) o.draw(); } </code></pre> <p>and this is the error:</p> <pre><code>Uncaught TypeError: Object 0 has no method 'draw' </code></pre> <p>i get a similar error trying to access the variables for that object. It seems that after i add them to the list js forgets about what type they are? - because when i print the array it is full of [Object object]'s</p> <p>thanks.</p>
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    1. COOff topic, but take your `draw` method out of the constructor, and place it once on the `prototype`. `Square.prototype.draw = func...`
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    2. COThanks, new to JS, any good resources for objects especially; I've read some conflicting things.
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