I have a createTable function that receives a collection of nodes (or an array of nodes), then I am able to draw a table.
I am switching to cytoscape.js now, and I really don't know how to have a listener to my select event properly.
Doing this:
cy.on('select', 'node', function(event){
window["selectedNodes"] = cy.$('node:selected');
});
I do have all information I need to draw my table, but I cannot call my createTable function inside it because it will call my function several times (once per node selected).
I've already tried to use cy.on and cy.once, but without success.
Here is my question:
How can I have a listener to my selection event, get ALL selected nodes and call (only once) my createTable function ?
I can also obtain all selected node using this:
cy.elements('node:selected', console.log("my CallBack function"));
But as it is outside an event listener (select / click) it doesn't work as I need.
Please, any help is appreciated.
Thank you.
Debounce your callback so if multiple events come in one after another, then they are effectively batched:
var timeout;
cy.on('select', 'node', function(event){
clearTimeout( timeout );
timeout = setTimeout(function(){
window["selectedNodes"] = cy.$('node:selected');
// and so on...
}, 100); // may have to adjust this val
});
Related
I am trying to figure it out if there is a function in the Bacon.js API that allows to subscribe to an EventStream and when the first event fires up, the handle is unsubscribed. The way to do it that I know is the following:
let stream = new Bacon.Bus();
stream.onValue(val => {
doSomething(val);
return Bacon.noMore;
});
But is there something like stream.onValueOnce that automatically unsubscribe the handler after it is executed?
I also know that there is the Bacon.once that creates a EventStream that returns a single value and then ends the stream but this is not what I am looking for.
Update
As Bless Yahu sais, take or first methods can be used. To be more specific, you have to call it from the created eventStream like that:
let stream = new Bacon.Bus();
stream.first().onValue(val => {
doSomething(val);
});
Here is a fiddle that shows it:
https://fiddle.jshell.net/3kjtwcwy/
How about stream.take(1)? https://baconjs.github.io/api.html#observable-take
Or stream.first()? https://baconjs.github.io/api.html#observable-first
Let's say we have a simple Backbone View, like this:
class MyView extends Backbone.View
events:
'click .save': 'onSave'
onSave: (event) ->
event.preventDefault()
# do something interesting
I want to test that event.preventDefault() gets called when I click on my element with the .save class.
I could test the implementation of my callback function, pretty much like this (Mocha + Sinon.js):
it 'prevents default submission', ->
myView.onSave()
myView.args[0][0].preventDefault.called.should.be.true
I don't think it's working but this is only to get the idea; writing the proper code, this works. My problem here is that this way I'm testing the implementation and not the functionality.
So, my question really is: how can I verify , supposing to trigger a click event on my .save element?
it 'prevents default submission', ->
myView.$('.save').click()
# assertion here ??
Thanks as always :)
Try adding a listener on the view's $el, then triggering click on .save, then verify the event hasn't bubbled up to the view's element.
var view = new MyView();
var called = false;
function callback() { called = true; }
view.render();
// Attach a listener on the view's element
view.$el.on('click', callback);
// Test
view.$('.save').trigger('click');
// Verify
expect(called).toBeFalsy();
So you want to test that preventDefault is called when a click event is generated, correct?
Couldn't you do something like (in JavaScript. I'll leave the CoffeeScript as an exercise ;)):
var preventDefaultSpy;
before(function() {
preventDefaultSpy = sinon.spy(Event.prototype, 'preventDefault');
});
after(function() {
preventDefaultSpy.restore();
});
it('should call "preventDefault"', function() {
myView.$('.save').click();
expect(preventDefaultSpy.callCount).to.equal(1);
});
You might want to call preventDefaultSpy.reset() just before creating the click event so the call count is not affected by other things going on.
I haven't tested it, but I believe it would work.
edit: in other words, since my answer is not that different from a part of your question: I think your first approach is ok. By spying on Event.prototype you don't call myView so it's acting more as a black box, which might alleviate some of your concerns.
I am trying out dojotoolkit 1.8 and cant figure out how to hook up an onchange event for a dojo/form/select
Nothing happens with this
require(["dojo/dom","dojo/on"], function(dom,on){
on(dom.byId("myselect"),"change",function (evt){
alert("myselect_event");
});
If instead, the following hook into click works:
on(dom.byId("myselect"),"click",function (evt){
but i want to capture the value after user clicks and changes
I am sure it is simpler than going back to Plain ol javascript onChange...
Thx
You could try something like this:
var select = dijit.byId('myselect');
select.on('change', function(evt) {
alert('myselect_event');
});
I've seen this in the reference-guide multiple times, eg in the dijit/form/select' s reference-guide at 'A Select Fed By A Store'.
Maybe it even returnes the handle, i haven't looked this up so far. But i guess it should work.
EDIT:
Considering #phusick's comment, i want to add, that you could also simply change the "change" to "onChange" or the dom to dijit within calling on(...)
Following in the footsteps of #nozzleman's answer try
var select = registry.byId('myselect');
select.on('change', function(evt) {
alert('myselect_event');
});
If you use on instead of connect then you don't have to write onChange, you can simply write change.
Similar to above answers do a dijit.ById to find the correct element and then register the 'onItemClick' event.
creating the select dropdown programatically appends a _menu to whatever node you create the select items so 'search' becomes 'search_menu' on a page init you can do the following:
dojo.connect(dijit.byId('search_menu'),'onItemClick',function(){
//console.log("search menu");
doSearch('recreation');
});
As others have pointed out, you're trying to access the Dijit using DOM. Also, the parameter to the anonymous function for the "change" event is the value selected by the user, not the event itself.
Here's your code modified to access the Dijit and process the "change" event:
require(["dijit/registry", "dojo/on"], function(registry, on) {
on(registry.byId("myselect"), "change", function (value) {
alert("change_event.value = " + value);
});
});
Late to the party, but I recently ran into the issue. Hopefully my answer will help some poor soul maintaining some legacy code. The answer is for combobox but worked for select as well -
onChange not sufficient to trigger query from Dojo Combobox. Need to attach listener to dropdown items.
select.dropDown.on("itemClick", function(dijit, event) {
var node = dijit.domNode;
console.log(domAttr.get(node, "data-info-attribute"));
// or
console.log(node.dataset.infoAttribute);
});
Ref: https://stackoverflow.com/a/12422155/4564016
How can I receive all events attached to an element with dojo?
dojo.query('#mydiv') // which events does #mydiv has?
To get all events on a DOM element:
// Get my div
myDiv = dojo.byId("myDiv");
// Obtain all event-related attributes
var events = dojo.filter(
myDiv.attributes,
function(item) {
return item.name.substr(0, 2) == 'on';
}
);
// Execute first found event, just for fun
eval(events[0].value);
If you get myDiv using dojo.query, remember that dojo.query returns an array, so your element would be in myDiv[0].
This solution does not work with events attached with dojo.connect. There probably is a way to extract this info from Dojo inner workings, but you would have to delve into the source code to understand how.
Another option is that you explicitly manage all dojo.connect events with a global registry. You could use dojox.collections to make this easier. For example, creating a global registry whose keys will be the dom nodes, and values will be the handles returned by dojo.connect (these handles contain the dom node, the type of event and the function to execute):
// On startup
dojo.require(dojox.collections.Dictionary);
eventRegistry = new dojox.collections.Dictionary();
...
// Registering an event for dom node with id=myDiv
var handle1 = dojo.connect(dojo.byId("myDiv"), "onclick", null, "clickHandler");
// Check if event container (e.g. an array) for this dom node is already created
var domNode = handle1[0];
if (!eventRegistry.containsKey(domNode))
eventRegistry.add(domNode, new Array());
eventRegistry.item(domNode).push(handle1);
...
// Add another event later to myDiv, assume container (array) is already created
var handle2 = dojo.connect(dojo.byId("myDiv"), "onmouseover", null, "mouseHandler");
eventRegistry.item(domNode).push(handle2);
...
// Later get all events attached to myDiv, and print event names
allEvents = eventRegistry.item(domNode);
dojo.forEach(
allEvents,
function(item) {
console.log(item[1]);
// Item is the handler returned by dojo.connect, item[1] is the name of the event!
}
);
You can hide the annoying check to see if event container is already created by creating a subclass of dojox.collections.Dictionary with this check already incorporated. Create a js file with this path fakenmc/EventRegistry.js, and put it beside dojo, dojox, etc:
dojo.provide('fakenmc.EventRegistry');
dojo.require('dojox.collections.Dictionary');
dojo.declare('fakenmc.EventRegistry', dojox.collections.Dictionary, {
addEventToNode : function(djConnHandle) {
domNode = djConnHandle[0];
if (!this.containsKey(domNode))
this.add(domNode, new Array());
this.item(domNode).push(djConnHandle);
}
});
Using the above class you would have to dojo.require('fakenmc.EventRegistry') instead of 'dojox.collections.Dictionary', and would simply directly add the dojo connect handle without other checks:
dojo.provide('fakenmc.EventRegistry');
eventRegistry = new fakenmc.EventRegistry();
var handle = dojo.connect(dojo.byId("myDiv"), "onclick", null, "clickHandler");
eventRegistry.addEventToNode(handle);
...
// Get all events attached to node
var allEvents = eventRegistry.item(dojo.byId("myDiv"));
...
This code is not tested, but I think you get the idea.
If its only for debugging purpose. You can try dijit.byId("myId").onClick.toString(); in your firebug console and you can see the entire onclick code this works even if the function is anonymous you can view the content of anonymous content.
I have a page of checkboxes, in some cases more than 100. I'm currently doing this:
$('form[name=myForm] input[name=myCheckbox]').change(function(){
var numChkd = $('input[name=myCheckbox]:checked').size();
console.log(numChkd);
};
But as you could imagine this can get wicked slow. Is there a better way to bind an event to multiple elements? This works, but I want to know if there is a better way?
You can bind an event to the parent container that will wrap all of the checkboxes and then check if the object that caused an event is a checkbox. This way you only bind one event handler. In jQuery you can use $.live event for this.
Don't recount every time a checkbox changes. Just use a global variable, like this:
var CheckboxesTicked = 0;
$(document).ready(function() {
CheckboxesTicked = $(":checkbox:checked").length;
$(":checkbox").change(function() {
if ($(this).is(":checked")) {
CheckboxesTicked += 1
} else {
CheckboxesTicked -= 1
}
});
});
Btw, the documentation states that you'd better use .length instead of .size() performance wise.
You could create a container element (like a Div with no styling) and attach the event handler to the container. That way, when the change() event happens on one of the checkboxes and percolates up the DOM, you'll catch it at the container level. That's one way to make this faster.
You should use .delegate(). One binding on a parent element can replace all the individual bindings on the child elements. It's perfect for this situation (and also solves the problem of attaching behavior to dynamically-added elements, should the need arise).
$('form[name=myForm]').delegate('input[name=myCheckbox]','change', function(){
var numChkd = $(this).siblings(':checked').length; // assuming siblings
console.log(numChkd);
});
This is how I would approach it:
$('form[name=myForm]').each(function() {
var $form = $(this),
$boxes = $form.find('input[name=myCheckbox]');
$form.delegate('input[name=myCheckbox]', 'change', function() {
var numChkd = $boxes.filter(':checked').length;
console.log(numChkd);
});
});
This takes advantage of caching the $boxes selection. It will look for all the boxes when it sets up the event. It uses .delegate() to attach an event to the form which will get fired anytime an child input[name=myCheckbox] creates a change event. In this event handler, you can easily filter the already obtained list of checkboxes by which ones are :checked and get the length of the matched elements. (The documentation for .size() basically states there is no reason to ever use it... It just returns this.length anyway...)
See this fiddle for a working demo
demo: http://jsfiddle.net/kKUdm/
$(':checkbox').change(function(){
if($(this).is(':checked')){
var name = $(this).attr('name');
var value = $(this).val();
console.log(name + ':' + value);
}
});
Var $chks = $(":checkbox");
Var ChkCount =0;
Var chktimer =0;
Function updateChkCount(){
ChkCount = $chks.filter(":checked").length;
$chks.end();
// do something witb ChkCount
}
$chks.bind("check change", function(){
clearInterval(chktimer);
chktimer = setInterval("updateChkCount()",250);
});