I have searched stackoverflow for a solution to this but nothing has worked.
I don't see why it shouldn't. My code looks as such:
A preloaded eventListener:
obj.container.on("click", Capture, null, false, [data]);
function Capture(evt, data){
}
this works as expected.
Now if I want to remove it with a condition:
if(state){
obj.container.off("click", Capture);
}
Does not work as expected. What am I doing wrong?
Have a look at the docs. The on method returns a closure, which is used to maintain scope. You must use that instead to remove the listener.
var closure = obj.on("click", listener);
obj.off("click", closure);
http://www.createjs.com/Docs/EaselJS/classes/DisplayObject.html#method_on
Related
I have below code to create column:
DTColumnBuilder.newColumn(null).withTitle('Validation').renderWith(validationRenderer)
and render function:
function validationRenderer(data, type, full, meta) {
.......
}
Now, I want to pass custom parameters to validationRenderer so that I can access it inside the function, like below:
DTColumnBuilder.newColumn(null).withTitle('Validation').renderWith(validationRenderer('abc'))
function validationRenderer(data, type, full, meta, additionalParam) {
// do something with additionalParam
}
I could not find it in the documentation but there must be something to pass additional parameters in meta as per the reference from here
Yes, you can. Or, better, you technically can, but you may use a clever workaround to handle your issue.
I had this issue today, and found a pretty sad (but working) solution.
Basically, the big problem is that the render function is a parameter passed to the datatable handler, which is (of course) isolated.
In my case, to make a pratical example, I had to add several dynamic buttons, each with a different action, to a dynamic datatable.
Apparently, there was no solution, until I thought the following: the problem seems to be that the renderer function scope is somewhat isolated and unaccessible. However, since the "return" of the function is called only when the datatable effectively renders the field, you may wrap the render function in a custom self-invoking-anonymous-function, providing arguments there to use them once the cell is being rendered.
Here is what I did with my practical example, considering the following points:
The goal was to pass the ID field of each row to several different custom functions, so the problem was passing the ID of the button to call when the button is effectively clicked (since you can't get any external reference of it when it is rendered).
I'm using a custom class, which is the following:
hxDatatableDynamicButton = function(label, onClick, classNames) {
this.label = label;
this.onClick = onClick;
this.classNames = this.classNames || 'col5p text-center';
}
Basically, it just creates an instance that I'm later using.
In this case, consider having an array of 2 different instances of these, one having a "test" label, and the other one having a "test2" label.
I'm injecting these instances through a for loop, hence I need to pass the "i" to my datatable to know which of the buttons is being pressed.
Since the code is actually quite big (the codebase is huge), here is the relevant snippet that you need to accomplish the trick:
scope.datatableAdditionalActionButtons.reverse();
scope._abstractDynamicClick = function(id, localReferenceID) {
scope.datatableAdditionalActionButtons[localReferenceID].onClick.call(null, id);
};
for (var i = 0; i < scope.datatableAdditionalActionButtons.length; i++) {
var _localReference = scope.datatableAdditionalActionButtons[i];
var hax = (function(i){
var _tmp = function (data, type, full, meta) {
var _label = scope.datatableAdditionalActionButtons[i].label;
return '<button class="btn btn-default" ng-click="_abstractDynamicClick('+full.id+', '+i+')">'+_label+'</button>';
}
return _tmp;
})(i);
dtColumns.unshift(DTColumnBuilder.newColumn(null).notSortable().renderWith(hax).withClass(_localReference.classNames));
}
So, where is the trick? the trick is entirely in the hax function, and here is why it works: instead of passing the regular renderWith function prototype, we are using a "custom" render, which has the same arguments (hence same parameters) as the default one. However, it is isolated in a self invoking anonymous function, which allows us to arbitrarely inject a parameter inside it and, so, allows us to distinguish, when rendering, which "i" it effectively is, since the isolated scope of the function is never lost in this case.
Basically, the output is as follow:
And the inspection actually shows that elements are effectively rendered differently, hence each "i" is being rendered properly, while it wouldn't have if the function wouldn't have been wrapped in a self invoking anonymous function:
So, basically, in your case, you would do something like this:
var _myValidator = (function(myAbcParam){
var _validate = function (data, type, full, meta) {
console.log("additional param is: ", myAbcParam); // logs "abc"
return '<button id="'+myAbcParam+'">Hello!</button>'; // <-- renders id ="abc"
}
return _validate ;
})('abc');
DTColumnBuilder.newColumn(null).withTitle('Validation').renderWith(_myValidator);
// <-- note that _myValidator is passed instead of "_myValidator()", since it is already executed and already returns a function.
I know this is not exactly the answer someone may be expecting, but if you need to accomplish something that complex in datatable it really looks like the only possible way to do this is using a self invoking anonymous function.
Hope this helps someone who is still having issues with this.
I was hoping I could get some input on how to use Knockout components in an object-oriented fashion using Object.create (or equivalent). I'm also using Postbox and Lodash, in case some of my code seems confusing. I've currently built a bunch of components and would like to refactor them to reduce code redundancy. My components, so far, are just UI elements. I have custom input boxes and such. My initial approach was as follows, with some discretion taken to simplify the code and not get me fired :)
// Component.js
function Component() {
var self = this
self.value = ko.observable()
self.initial = ko.observable()
...
self.value.subscribeTo('revert', function() {
console.log('value reverted')
self.value(self.initial())
}
}
module.exports = Component
// InputBox.js
var Component = require('./Component')
var _ = require('lodash')
function InputBox(params) {
var self = this
_.merge(self, params) // quick way to attach passed in params to 'self'
...
}
InputBox.prototype = Object.create(new Component)
ko.components.register('input-box', InputBox)
Now this kind of works, but the issue I'm having is that when I use the InputBox in my HTML, I pass in the current value as a parameter (and it's also an observable because the value is retrieved from the server and passed down through several parent components before getting to the InputBox component). Then Lodash merges the params object with self, which already has a value observable, so that gets overwritten, as expected. The interesting part for me is that when I use postbox to broadcast the 'revert' event, the console.log fires, so the event subscription is still there, but the value doesn't revert. When I do this in the revert callback, console.log(self.value(), self.initial()), I get undefined. So somehow, passing in the value observable as a parameter to the InputBox viewmodel causes something to go haywire. When the page initially loads, the input box has the value retrieved from the server, so the value observable isn't completely broken, but changing the input field and then hitting cancel to revert it doesn't revert it.
I don't know if this makes much sense, but if it does and someone can help, I'd really appreciate it! And if I can provide more information, please let me know. Thanks!
JavaScript does not do classical inheritance like C++ and such. Prototypes are not superclasses. In particular, properties of prototypes are more like static class properties than instance properties: they are shared by all instances. It is usual in JS to have prototypes that only contain methods.
There are some libraries that overlay a classical-inheritance structure onto JavaScript. They usually use "extends" to create subclasses. I don't use them, so I can't recommmend any in particular, but you might look at Coffeescript if you like the classical-inheritance pattern.
I often hear "favor composition over inheritance," but I generally see a lot of emphasis on inheritance. As an alternative, consider Douglas Crockford's "class-free object-oriented programming", which does away with inheritance entirely.
For what you're trying to do here, you probably want to have InputBox initialize itself with Component, something like:
function InputBox(params) {
var self = this
Component.bind(self)(); // super()
_.merge(self, params) // quick way to attach passed in params to 'self'
...
}
The new, merged, value will not have the subscription from Component, because the subscription is particular to Component's instance of the observable, which will have been overwritten.
To everyone who responded, thank you very much! I've found a solution that works better for me and will share it here in case anyone is interested.
// Component.js (only relevant parts shown)
function Component(params) {
var self = this
_.merge(self, params)
self.value.subscribeTo('some event', function() {
// do some processing
return <new value for self.value>
}
module.exports = Component
// InputBox.js
var Component = require('./component')
function InputBox(params) {
var self = this
Component.call(self, params)
}
By taking this approach, I avoid the headache of using prototypes and worrying about the prototype chain since everything Component does is done directly to the "inheriting" class. Hope this helps someone else!
I want to override dijit._CssStateMixin's domReady() method.
Is there any way to override that instead of changing the listener mechanism in Dojo.
I tried overriding _cssMouseEvent() method in simple javascript, but it still does invoke dijit's _cssMouseEvent() from domReady().
I have tried following approach:
dojoConfig = {
map: {
'dijit/_CssStateMixin': {
'dojo/domReady': 'app/noop'
}
}
};
I have added 'app' folder and then 'noop.js' inside that.
noop.js has nothing in it:
define([], function () {
return function () {};
});
Even after this I can see that dijit.js's _CssStateMaxin domReady() getting called from listener.apply (code snippet pasted below)
var addStopImmediate = function(listener){
return function(event){
if(!event.immediatelyStopped){// check to make sure it hasn't been stopped immediately
event.stopImmediatePropagation = stopImmediatePropagation;
return listener.apply(this, arguments);
}
};
}
If your ultimate goal is to prevent the domReady callback in dijit/_CssStateMixin from running, your simplest bet is likely to re-map dojo/domReady to a different module that doesn't call the callback at all, when loaded via dijit/_CssStateMixin.
NOTE: Stripping out these handlers might have adverse visual effects on Dijit widgets which inherit _CssStateMixin, since it may hinder the application of Dijit CSS classes related to hover and focus. But if your concern is that _CssStateMixin is hampering performance, it may at least be worth a try to confirm or deny your suspicion.
First we have to create a simple module that returns a function that does nothing, which we will later substitute for dojo/domReady when loaded by dijit/_CssStateMixin, so that it can still call domReady but it won't execute the callback it passes.
For simplicity's sake I'll assume you already have a custom package that you can easily add a module to; for this example I'll assume it's called app. Let's create app/noop:
define([], function () {
return function () {};
});
Now let's configure the loader to map app/noop in place of dojo/domReady specifically when loaded by dijit/_CssStateMixin:
var dojoConfig = {
...,
map: {
'dijit/_CssStateMixin': {
'dojo/domReady': 'app/noop'
}
},
...
};
Now the offending domReady callback should no longer be run.
If you're curious about map, you can read more about it in this SitePen FAQ.
I have a safari extension popover that needs to communicate with its global page. From a content-script I am using
safari.self.tab.dispatchMessage(name,data);
to accomplish that. From a popover I didn't find a way to do that. I know that I can access methods in the global page directly
safari.extension.globalPage.contentWindow
but my goal was to reuse code fragments that are already used in content-scripts. I do the same for the chrome version of the plugin.
Is there code for a little clever proxy that emulates
safari.self.tab.dispatchMessage(name,data);
from the popover?
To be honest it's probably just easier to have different code in your popover and injected scripts. If you really want, you could do something like this:
function dispatchMessage(name, message) {
if (safari.self.tab) {
safari.self.tab.dispatchMessage(name, message);
} else if (safari.extension.globalPage.contentWindow) {
safari.extension.globalPage.contentWindow.handleMessage({name: name, message: message});
}
}
Then just use dispatchMessage('foo', 'bar') in both your popover and injected scripts. It's a bit hacky though, because the message event object normally has more information on it than just the name and message, and you have to ensure that your handleMessage function is actually the same function that is assigned as the message event listener in the global page.
A simplistic way to accomplish reusing your message-based content script code in your popover is by wrapping the safari.self.tab.dispatchMessage calls in an abstraction function that I'll describe below...
But first, you need to make sure to have a single named handler function in your global page that handles all messages, like this:
function handleMessage(evt) {
switch (evt.name) {
case 'Message1':
// do something with evt.message
break;
case 'Message2':
// do something else with evt.message
break;
}
}
safari.application.addEventListener('message', handleMessage, false);
If you have separate handlers for each different message, or if you're using an anonymous function, this approach will not work.
Now, the wrapper function that goes in your popover and content scripts is very simple:
function tellGlobalPage(msgName, msgData) {
if (safari.self instanceof SafariExtensionPopover) {
// this script is running in a popover
var fakeMsgEvt = { name: msgName, message: msgData };
safari.extension.globalPage.contentWindow.handleMessage(fakeMsgEvt);
} else {
// this script is a content script
safari.self.tab.dispatchMessage(msgName, msgData);
}
}
And then instead of safari.self.tab.dispatchMessage(name, data), you use tellGlobalPage(name, data).
Please note that this simplistic approach doesn't deal with roundtrip messaging, where the popover or content script sends a message to the global page, and the global page replies with another message. There are other approaches that can handle that.
So I think I maybe missing something with Ext.Ajax.request();
So I have code that does the following:
Ext.Ajax.request({
url : 'myurl',
success : function(){
alert('success 1');
},
callback : function(){
alert('callback');
}
});
Then later I make another ajax call like this:
Ext.Ajax.request({
url : 'myurl',
success : function(){
alert('success 2');
}
});
If i don't define a callback function the old one from the first call is still set. So when it runs it still calls the old callback function defined earlier. So I add listeners to the
Ext.Ajax.on('beforerequest', function(c, o, e){
//The options has all my previous options
});
So I put a break point in here and looked at the options, and if on my second call or any other ajax call after do not override callback or any other options with an emptyFunction() or any other request config the previous values stays. So if on my second call I didn't redefine the success function the first calls success function would still be there. Is there a way to clear all previous options, on the next call? I could just clear them on each new call. But I don't understand why if the calls are unrelated my options from the last call remain?
As the docs states, Ext.Ajax is a singleton.
If you look at its code, you'll see the the option config will remain between calls.
So I'm afraid to say that you are using it the wrong way. Ideally, you should define what happens upon success or failure with each call.
It does appear though that this will work:
var iAjax = new Ext.data.Connection();
iAjax.request({
// unique config here.
});