We Keep Coding

Assigning callback events from an array of strings (PIXI.js)

all. I have kind of a doozy of a problem, that could be solved really simply, if I just wanted to duplicate the code. I mean, really, it's a small part of a project that I'm doing just to see if I can, more than anything else, but it is bothering me since I've thought it up.
The Project
For fun, I've decided to take someone's ActionScript 3, text-based game engine and convert it to TypeScript and ultimately JavaScript using PixiJS.
The thing is, there are still 20213 errors to be fixed running tsc, so I could just leave this to a later date. But I was working on the Button class, which they defined as a subclass of MovieClip. That's fine; I just responded by reading up on PIXI buttons, and they seem fairly straightforward. Just, in the button's constructor, add something akin to the following lines:
export class Button extends PIXI.Sprite {
private _callback : Function;
private _height : number;
private _width : number;
public get callback() : Function { return this._callback; }
public set callback(fn : Function) {this._callback = fn; }
public get height() : number { return this._height; }
public set height(h : number) {this._height = h; }
public get width() : number {return this._width; }
public set width(w : number) {this._width = w; }
public constructor(width = 180, height = 90, callback: Function = null){
super(new PIXI.Texture(new PIXI.BaseTexture(GLOBAL.BTN_BACK, PIXI.SCALE_MODES.NEAREST)));
this.callback = callback;
this.width = width;
this.height = height;
this.buttonMode = true;
this.interactive = true;
this.anchor.set(0.5);
this.on('mousedown', this.callback)
.on('touchstart', this.callback);
}
}
That's a bit of a simplified version, and the version I did on Codepen uses a Container and a private _sprite field instead (as well as a ColorMatrixFilter that doesn't work too well on the black icons I picked out, but that's not really important for this question), but that's roughly the gist of how it's done.
The Problem
The problem is that, in the codepen, I'd like to do the following:
// assign `this.callback` to each of the following events:
let that = this;
['click','mousedown','touchstart'].map(evt => that.on(evt, that.callback});
with a simple call being passed in their constructors elsewhere:
for (let n = 0; n < 5; ++n){
btnArray.push(new Button(16, 16, () => console.info('You pushed button %d', n)));
}
but I'm not getting anything from them, even in the Chrome Console. I even logged that ColorMatrixFilter I mentioned earlier, to see if it was console.info that was wrong. Nope. So now, I'm confused on that. I was hoping to be able to just make a GLOBAL (a legacy static object from the AS source) key to iterate through for the events, but it looks like that's not happening.
The Questions
Is what I'm trying to do feasible, if odd? Is it blocked by a security feature (for which I'd be grateful)? If not, what am I doing wrong?
Should I even worry about setting all these different event handlers, or is just listening to click enough?

When an arrow function like your event map is executed the this context is not set, so any code that references this is going to get the current value, including any functions your map calls.
Replace your event map with the following:
['click','mousedown','touchstart'].map(function(evt) { that.on(evt, that.callback} } );
A demonstration:
function Named(x) {
this.name = x;
}
var foo = new Named("foo");
var bar = new Named("bar");
var showFunc = function show() {
// this is context dependant
console.log(this.name);
}
var showArrow;
// this is the window
showArrow = () => console.log(this.name);
var fooShowArrow;
(function() {
// this is foo
that = this;
fooShowArrow = () => console.log(that.name);
}).apply(foo);
var example = function(func) {
// For the demo, at this point, this will always be bar
func.apply(this, [ "arbitrary value" ]);
}
// explicitly set the current "this" to bar for the execution of these functions
example.apply(bar, [showFunc]); // works
example.apply(bar, [showArrow]); // fails, this is still the window
example.apply(bar, [fooShowArrow]); // fails, this is still foo

Javascript / Why mycode is not synchronous

I have discover that a custom code is not syncronous as I thought.
I have this pseudo code:
ObjectA = function ()
{
var pointer;
var value =[];
this.set_pointer = function (p) {pointer = p;}
this.return_value = function () {return value[pointer];}
}
ObjectB = function ()
{
var SCOPE = this;
var OBJ = new ObjectA();
....
this.reset = function ()
{ OBJ.set_pointer(0);}
this.draw = function (what)
{
SCOPE.update();
OBJ.set_pointer(from);
OBJ.get_value();
// do somethings with Three.js
// draw some lines and some little pointclouds.
// do some things
// update two text elements
}
}
Main = new ObjectB();
Main.draw(7);
Main.reset();
ObjectA is using arraybuffers, dataviews and typedarrays.
ObjectB is using Three.js to draw some very symple 3D things.
The problem is inside 'draw'.
OBJ.get_value(); is using the pointer value 0 (zero) instead 7.
Abnormally (as I think) main.draw(7) is not executed first and later Main.reset(); It seems that Main.reset() is inmediatelly executed, so I have 0 (zero)
I'm not going to wait any DOM synchronism.
What can be the reason of this bechaviour?. Maybe the Three,js use ? The OOP style I'm using ?
Is there any way to check why is this happen?
Any idea would be appreciated
NOTE: Sorry for use the Three.js tag.

SOLVED
I have found the reason (or I think ) of a NO synchonism
Sometimes 'this' could be pointing to 'window' instead of the self instance of your object.
Sometimes, a bad use of this (when it is 'window') can raise an error you have not taken into account. Then a next line of code can be executed, and sometimes you can have the impression of an incorrect (not syncronous) operation.
So.... review the bad use of 'this'....

Creating a custom d3 layout

I need to create a custom d3 layout that is somewhat close to a treemap but in a triangular style. Here's a screenshot so that you can understand:
Pyramid layout
As you can see, it works pretty neat and fits my need.
To code it, i've based the code on the treemap layout code:
d3.layout.pyramid= function () {
var hierarchy = d3.layout.hierarchy(), round = Math.round, size = [ 1, 1 ], padding = 0;
function populate (nodes, currentHeight, currentHeightPadded, currentBase, currentSumedWeight) {
...
}
function populate_layers (layer, nodes,currentHeight,currentLength, currentSumedArea,currentSumedWeight) {
...
}
function pyramid(d) {
var nodes = hierarchy(d), root = nodes[0];
populate(root.children.slice(),0,0,0,0);
return nodes;
}
pyramid.padding = function(x) {
if (!arguments.length) return padding;
padding = x;
return pyramid;
};
pyramid.size = function(x) {
if (!arguments.length) return size;
size = x;
return pyramid;
};
return d3_layout_hierarchyRebind(pyramid, hierarchy);
};
My problem is, to do so, I've had to directly edit the d3.v2.js file, because some private functions are not accessible from outisde, in my case d3_layout_hierarchyRebind.
Clearly I know it´s not the best practice at all but I can't manage to externalize my file in a separate script cause d3_layout_hierarchyRebindis not visible from the outside.
I don't know if it's a d3- or javascript-related issue but I'd like to know if you could help me solve this little problem.
Thank's in advance!

Just copy and paste the d3.layout.pyramid function into a new file and rename functions as necessary so it doesn't conflict with the d3 library. Likely everything will be private so only the outermost function will need to be renamed. You probably won't have to namespace it to "d3". That is to say, this should work:
var myPyramidLayout = function () {
...
}

detecting object-reference duplication across JavaScript files

I have a number of files with contents like this:
function hello() {
...
element1.text = foo.locale.lorem;
element2.text = foo.locale.ipsum;
...
elementn.text = foo.locale.whatever;
...
}
function world() {
...
var label = bar.options.baz.blah;
var toggle = bar.options.baz.use_toggle;
...
}
This could be written more efficiently, and also be more readable, by creating a shortcut to the locale object:
function hello() {
var loc = foo.locale;
...
element1.text = loc.lorem;
element2.text = loc.ipsum;
...
elementn.text = loc.whatever;
...
}
function world() {
var options = bar.options.baz;
...
var label = options.blah;
var toggle = options.use_toggle;
...
}
Is there a simple way to detect occurrences of such duplication for any arbitrary object (it's not always as simple as "locale", or foo.something)?
Basically, I wanna know where lengthy object references appear two or more times within a function.
Thanks!

Are you talking about something like LINT? e.g. something externally that can report such object references or internally like looping over the window object

Javascript minifiers will do this for you. Not sure if thats what you're looking for. Heres a good js minifier http://jscompress.com/

Javascript function objects

I edited the question so it would make more sense.
I have a function that needs a couple arguments - let's call it fc(). I am passing that function as an argument through other functions (lets call them fa() and fb()). Each of the functions that fc() passes through add an argument to fc(). How do I pass fc() to each function without having to pass fc()'s arguments separately? Below is how I want it to work.
function fa(fc){
fc.myvar=something
fb(fc)
}
function fb(fc){
fc.myothervar=something
fc()
}
function fc(){
doessomething with myvar and myothervar
}
Below is how I do it now. As I add arguments, it's getting confusing because I have to add them to preceding function(s) as well. fb() and fc() get used elsewhere and I am loosing some flexibility.
function fa(fc){
myvar=something
fb(fc,myvar)
}
function fb(fc,myvar){
myothervar=something
fc(myvar,myothervar)
}
function fc(myvar,myothervar){
doessomething with myvar and myothervar
}
Thanks for your help
Edit 3 - The code
I updated my code using JimmyP's solution. I'd be interested in Jason Bunting's non-hack solution. Remember that each of these functions are also called from other functions and events.
From the HTML page
<input type="text" class="right" dynamicSelect="../selectLists/otherchargetype.aspx,null,calcSalesTax"/>
Set event handlers when section is loaded
function setDynamicSelectElements(oSet) {
/**************************************************************************************
* Sets the event handlers for inputs with dynamic selects
**************************************************************************************/
if (oSet.dynamicSelect) {
var ySelectArgs = oSet.dynamicSelect.split(',');
with (oSet) {
onkeyup = function() { findListItem(this); };
onclick = function() { selectList(ySelectArgs[0], ySelectArgs[1], ySelectArgs[2]) }
}
}
}
onclick event builds list
function selectList(sListName, sQuery, fnFollowing) {
/**************************************************************************************
* Build a dynamic select list and set each of the events for the table elements
**************************************************************************************/
if (fnFollowing) {
fnFollowing = eval(fnFollowing)//sent text function name, eval to a function
configureSelectList.clickEvent = fnFollowing
}
var oDiv = setDiv(sListName, sQuery, 'dynamicSelect', configureSelectList); //create the div in the right place
var oSelected = event.srcElement;
if (oSelected.value) findListItem(oSelected)//highlight the selected item
}
Create the list
function setDiv(sPageName, sQuery, sClassName, fnBeforeAppend) {
/**************************************************************************************
* Creates a div and places a page in it.
**************************************************************************************/
var oSelected = event.srcElement;
var sCursor = oSelected.style.cursor; //remember this for later
var coords = getElementCoords(oSelected);
var iBorder = makeNumeric(getStyle(oSelected, 'border-width'))
var oParent = oSelected.parentNode
if (!oParent.id) oParent.id = sAutoGenIdPrefix + randomNumber()//create an ID
var oDiv = document.getElementById(oParent.id + sWindowIdSuffix)//see if the div already exists
if (!oDiv) {//if not create it and set an id we can use to find it later
oDiv = document.createElement('DIV')
oDiv.id = oParent.id + sWindowIdSuffix//give the child an id so we can reference it later
oSelected.style.cursor = 'wait'//until the thing is loaded
oDiv.className = sClassName
oDiv.style.pixelLeft = coords.x + (iBorder * 2)
oDiv.style.pixelTop = (coords.y + coords.h + (iBorder * 2))
XmlHttpPage(sPageName, oDiv, sQuery)
if (fnBeforeAppend) {
fnBeforeAppend(oDiv)
}
oParent.appendChild(oDiv)
oSelected.style.cursor = ''//until the thing is loaded//once it's loaded, set the cursor back
oDiv.style.cursor = ''
}
return oDiv;
}
Position and size the list
function configureSelectList(oDiv, fnOnClick) {
/**************************************************************************************
* Build a dynamic select list and set each of the events for the table elements
* Created in one place and moved to another so that sizing based on the cell width can
* occur without being affected by stylesheet cascades
**************************************************************************************/
if(!fnOnClick) fnOnClick=configureSelectList.clickEvent
if (!oDiv) oDiv = configureSelectList.Container;
var oTable = getDecendant('TABLE', oDiv)
document.getElementsByTagName('TABLE')[0].rows[0].cells[0].appendChild(oDiv)//append to the doc so we are style free, then move it later
if (oTable) {
for (iRow = 0; iRow < oTable.rows.length; iRow++) {
var oRow = oTable.rows[iRow]
oRow.onmouseover = function() { highlightSelection(this) };
oRow.onmouseout = function() { highlightSelection(this) };
oRow.style.cursor = 'hand';
oRow.onclick = function() { closeSelectList(0); fnOnClick ? fnOnClick() : null };
oRow.cells[0].style.whiteSpace = 'nowrap'
}
} else {
//show some kind of error
}
oDiv.style.width = (oTable.offsetWidth + 20) + "px"; //no horiz scroll bars please
oTable.mouseout = function() { closeSelectList(500) };
if (oDiv.firstChild.offsetHeight < oDiv.offsetHeight) oDiv.style.height = oDiv.firstChild.offsetHeight//make sure the list is not too big for a few of items
}

Okay, so - where to start? :) Here is the partial function to begin with, you will need this (now and in the future, if you spend a lot of time hacking JavaScript):
function partial(func /*, 0..n args */) {
var args = Array.prototype.slice.call(arguments, 1);
return function() {
var allArguments = args.concat(Array.prototype.slice.call(arguments));
return func.apply(this, allArguments);
};
}
I see a lot of things about your code that make me cringe, but since I don't have time to really critique it, and you didn't ask for it, I will suggest the following if you want to rid yourself of the hack you are currently using, and a few other things:
The setDynamicSelectElements() function
In this function, you can change this line:
onclick = function() { selectList(ySelectArgs[0], ySelectArgs[1], ySelectArgs[2]) }
To this:
onclick = function() { selectList.apply(null, ySelectArgs); }
The selectList() function
In this function, you can get rid of this code where you are using eval - don't ever use eval unless you have a good reason to do so, it is very risky (go read up on it):
if (fnFollowing) {
fnFollowing = eval(fnFollowing)
configureSelectList.clickEvent = fnFollowing
}
And use this instead:
if(fnFollowing) {
fnFollowing = window[fnFollowing]; //this will find the function in the global scope
}
Then, change this line:
var oDiv = setDiv(sListName, sQuery, 'dynamicSelect', configureSelectList);
To this:
var oDiv = setDiv(sListName, sQuery, 'dynamicSelect', partial(configureSelectListAlternate, fnFollowing));
Now, in that code I provided, I have "configureSelectListAlternate" - that is a function that is the same as "configureSelectList" but has the parameters in the reverse order - if you can reverse the order of the parameters to "configureSelectList" instead, do that, otherwise here is my version:
function configureSelectListAlternate(fnOnClick, oDiv) {
configureSelectList(oDiv, fnOnClick);
}
The configureSelectList() function
In this function, you can eliminate this line:
if(!fnOnClick) fnOnClick=configureSelectList.clickEvent
That isn't needed any longer. Now, I see something I don't understand:
if (!oDiv) oDiv = configureSelectList.Container;
I didn't see you hook that Container property on in any of the other code. Unless you need this line, you should be able to get rid of it.
The setDiv() function can stay the same.
Not too exciting, but you get the idea - your code really could use some cleanup - are you avoiding the use of a library like jQuery or MochiKit for a good reason? It would make your life a lot easier...

A function's properties are not available as variables in the local scope. You must access them as properties. So, within 'fc' you could access 'myvar' in one of two ways:
// #1
arguments.callee.myvar;
// #2
fc.myvar;
Either's fine...

Try inheritance - by passing your whatever object as an argument, you gain access to whatever variables inside, like:
function Obj (iString) { // Base object
this.string = iString;
}
var myObj = new Obj ("text");
function InheritedObj (objInstance) { // Object with Obj vars
this.subObj = objInstance;
}
var myInheritedObj = new InheritedObj (myObj);
var myVar = myInheritedObj.subObj.string;
document.write (myVar);
subObj will take the form of myObj, so you can access the variables inside.

Maybe you are looking for Partial Function Application, or possibly currying?
Here is a quote from a blog post on the difference:
Where partial application takes a function and from it builds a function which takes fewer arguments, currying builds functions which take multiple arguments by composition of functions which each take a single argument.
If possible, it would help us help you if you could simplify your example and/or provide actual JS code instead of pseudocode.