Category Archives: dynamic

Proxy - (object always defined)

By Zevan | October 28, 2018

This uses a proxy to make sure all keys/props of an object are always defined.

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let spec = {
  get: (o, key) => {
    return o[key] != null ? o[key] : o[key] = O();
  },
  set: (o, key, v) => {
    o[key] = v;
  }
};
 
let O = () => {
  return new Proxy({}, spec);  
};
 
let dynamic = O();
dynamic.prop.creation = 'is interesting';
dynamic.prop.stuff.not.clear.what.this.could.be.used.for = 123;
 
// log out full structure
let f = (o) => {
  for (let i in o) {
    console.log(o[i]);
    if (typeof o[i] === 'object') f(o[i]);
  }
};
f(dynamic);

Outputs: 

Proxy {creation: "is interesting", stuff: Proxy}
is interesting
Proxy {not: Proxy}
Proxy {clear: Proxy}
Proxy {what: Proxy}
Proxy {this: Proxy}
Proxy {could: Proxy}
Proxy {be: Proxy}
Proxy {used: Proxy}
Proxy {for: 123}
123
Also posted in Object, es6, functions, javascript | Tagged , | Leave a comment

Bracket Syntax Reminder

By Zevan | March 9, 2010

If you haven't looked at every post on this site it's possible you've missed one of my favorite actionscript features.... Bracket Syntax:

CLICK HERE TO COPY
Actionscript:
  1. var s:Sprite = Sprite(addChild(new Sprite()));
  2. s["x"] = 100;
  3. s["y"] = 100;
  4.  
  5. s["graphics"]["beginFill"](0xFF0000);
  6. s["graphics"]["drawCircle"](0,0,10);
  7.  
  8. this["addChild"](s);

If you don't realize how powerful this is then there is something wrong with you (joking). If you don't see how powerful this is, take some time and think about it. You can use it to avoid lots of annoying repetitive code in state machines for instance. It's always important to keep things readable if you decide to go this route on a real project.

[EDIT ....and as Quasimondo mentioned there is a notable performance hit when using this syntax. So don't forget to keep that in mind.]


Here is a very old post showing some of the power of this trick.

Also posted in functions | Tagged , , | 4 Comments

JS Sketch Experiment

By Zevan | October 5, 2009
CLICK HERE TO COPY
Actionscript:
  1. [SWF(width=950, height=600)]
  2. with (graphics) beginFill(0xefefef), drawRect(0,0,stage.stageWidth, stage.stageHeight);
  3. var btn:Sprite = Sprite(addChild(new Sprite()));
  4. with (btn.graphics) beginFill(0x666666), drawRect(0,0,100,20);
  5. with(btn)  x=320, y=430, buttonMode = true;
  6. btn.addEventListener(MouseEvent.ROLL_OVER, function():void{
  7.   with(btn.graphics) clear(), beginFill(0x222222), drawRect(0,0,100,20);
  8. });
  9. btn.addEventListener(MouseEvent.ROLL_OUT, function():void{
  10.   with(btn.graphics) clear(), beginFill(0x666666), drawRect(0,0,100,20);
  11. });
  12. btn.addEventListener(MouseEvent.CLICK, function():void{
  13.     var res:*= ExternalInterface.call("function(){ plot=[]; colors=[]; " + txt.text + " return {plot:plot, colors:colors};}");
  14.     render((res == null) ? {plot:[], colors:[]} : res);
  15. });
  16.  
  17. var v:Shape = Shape(addChild(new Shape()));
  18. v.x = 700;
  19. v.y = 220;
  20. function render(obj:Object):void{
  21.     var plot:Array = obj.plot;
  22.     var colors:Array = obj.colors;
  23.     var leng:int = plot.length;
  24.     v.graphics.clear();
  25.     var inc:int = 0;
  26.     v.graphics.moveTo(plot[0], plot[1]);
  27.     for (var i:int = 2; i<leng; i+=2){
  28.         v.graphics.lineStyle(0,colors[inc++]);
  29.         v.graphics.lineTo(plot[i], plot[i + 1]);
  30.     }
  31. }
  32.  
  33.  
  34. var submit:TextField = TextField(btn.addChild(new TextField()));
  35. submit.defaultTextFormat = new TextFormat("_sans", 12);
  36. with(submit) textColor=0xFFFFFF, width=100, autoSize="center";
  37. with(submit) mouseEnabled = false,  text="submit";
  38.  
  39. var txt:TextField = TextField(addChild(new TextField()));
  40. with(txt) x = y = 20, type = "input", multiline=true;
  41. with(txt) width = 400, height = 400, border = true, background = 0xFFFFFF;
  42. txt.defaultTextFormat = new TextFormat("Monaco", 12);
  43. txt.text = "enter text";
  44. txt.addEventListener(MouseEvent.MOUSE_DOWN, onDown);
  45. function onDown(evt:MouseEvent):void{
  46.     txt.text = "";
  47.     txt.removeEventListener(MouseEvent.MOUSE_DOWN, onDown);
  48. }

This snippet is a mini code editor that allows the user to write javascript into a textfield - the javascript is then run using external interface. Optionally the javascript code can populate two arrays (plot and colors). If these arrays are populated flash, will render the data in each array using the Graphics class.

Have a look at the demo:

If you do something nice with this... post your javascript snippet as a comment and I'll add it to the JS Sketch page...

Also posted in Graphics, Math, external data, functions | Tagged , , , | Leave a comment

Counter Function

By Zevan | July 4, 2009
CLICK HERE TO COPY
Actionscript:
  1. var counter:Function = function(count:Array):Function{
  2.     var leng:int = count.length;
  3.     var index:int = 0;
  4.     return counter = function(reset:*=""):Function{
  5.         if (reset=="reset"){
  6.             index = 0;
  7.             return counter;
  8.         }else
  9.         if (reset is Array){
  10.             count = reset;
  11.             return counter;
  12.         }
  13.         trace(count[index % leng]);
  14.         index++;
  15.         return counter;
  16.     }
  17. }
  18.  
  19. // first time it's called you pass an array
  20. trace("count through the array:");
  21. // you can optionally call trigger the counter by calling the newly
  22. // returned function
  23. counter(["a","b","c"])();
  24. counter();
  25. counter();
  26. trace("change the array:");
  27. // here we choose to simply set the array and not trigger the counter
  28. counter([10,20,40,60,80]);
  29. counter();
  30. counter()
  31. trace("reset the counter:");
  32. // reset and the counter is called 3 times
  33. counter("reset")()()();
  34.  
  35. /*outputs :
  36. count through the array:
  37. a
  38. b
  39. c
  40. change the array:
  41. 10
  42. 20
  43. reset the counter:
  44. 10
  45. 20
  46. 40
  47. */

Today I felt like messing around with functions and this is the result. This snippet shows a strange and interesting technique to create a function that iterates through a given array in a few different ways.

I believe the technical term for this kind of thing is a continuation...

There are a bunch of other posts like this on actionsnippet. Some are purely experimental, others are actually quite useful... these can all be found in the functions category.

Also posted in functions | Tagged , , | Leave a comment