How to reference $(this) when using on() - this

I'm using on() to mimic live() and can't for the life of me figure out how to properly reference $(this) so it references the selector I passed in. Here's the code, $(this) returns "body" instead of "select".
$("body").on("change", "select", function(e){
console.log($(this));
});

try this
$(e.currentTarget);
e is actually the event arguments for the event and that's what you want I beleive.

You can use event.target to the the source of event.
Live Demo
$("body").on("change", "select", function(e){
console.log($(e.target));
});

Related

Is it better to reuse or recreate a reactive source in Meteor

I have a template called 'contacts'. Inside is an #each which renders the template 'contact'. The user can press the 'edit' button which sets a session variable with the mongo id of the edited row. The row then reactively re-renders into "edit" mode.
Template.contact.viewEditing = function() {
return Session.get("contactViewEditingId") === this._id;
}
The html uses the viewEditing helper a few times, for instance:
{{#if viewEditing}}
<div class="panel-heading">EDITING!</div>
{{/if}}
I need to bind some javascript in the .rendered(). I would like to check again if we are editing. I can think of 2 options:
Should I call Template.content.viewEditing() inside my template.rendered() ? Does this save on reactivity calculations?
Or should I just copy pasta the if statement. This option seems to violate DRY.
Option 1:
Template.contact.rendered = function() {
if( Template.contact.viewEditing.call(this.data) ) {
// Bind some fancy jQuery
bindEditInPlace(this.data);
}
}
Option 2:
Template.contact.rendered = function() {
if( Session.get("contactViewEditingId") === this._id ) {
// Bind some fancy jQuery
bindEditInPlace(this.data);
}
}
I think that putting {{viewEditing}} multiple times in your template doesn't "cost" anything extra. So logically I would think that using this helper elsewhere is better. Maybe I need more help understanding reactivity calculations. Thanks!
Helpers are run inside a Deps.Computation, which means that every time a reactive variable is referenced and modified in a helper, it will re-run.
Template.rendered is a callback that runs each time the template is re-rendered (which usually happens when a helper in the template is re-run reactively), but it is not itself a reactive computation.
So it doesn't matter using either the template helper or copy-pasting its code inside your rendered callback : both ways won't trigger a reactive computation invalidation because we are not inside one.
As far as DRY is concerned, you could refactor your code like this :
function isContactViewEditing(contactView){
return Session.equals("contactViewEditingId",contactView._id);
}
Template.contact.helpers({
viewEditing:isContactViewEditing
});
Template.contact.rendered=function(){
if(isContactViewEditing(this.data)){
//
}
};
I think saimeunt's answer is correct, especially if you have more complex logic in the function which you don't want to replicate.
Create a local function which you can re-use in both the helper and the .rendered callback.
If you had a case where you wanted to use a reactive source minus the reactivity you could make it non-reactive by wrapping it in a Deps.nonreactive function likes so:
Deps.nonreactive(function(){
//Reactive stuff here
});
Regarding reactivity concerns, pay attention to his change from using Session.get to Session.equals. Session.get will cause any reactive computation it is used in to re-calculate on every change of the session variable. So if you use this helper in multiple places with different ids, and you change the session variable, every single one will re-calculate and re-render the templates they are used in. Session.equals only invalidates a computation when the equality changes. So changing the session variable from one non-equal id to another non-equal id will not cause the computation/template to re-run when you use Session.equals.
For your specific example where the helper is only returning the result of a Session.equals you might consider creating a global handlebars helper that can do this for you with any session variable and any value. Like the following.
Handlebars.registerHelper('sessionEquals', function (key, value) {
return Session.equals(key, value);
});
Then in the template use it like so:
{{#if sessionEquals 'contactViewEditingId' _id}}
<div class="panel-heading">EDITING!</div>
{{/if}}
In the template when rendering an item that is editable add a unique class name to mark the item as editable. Then in your Template.rendered callback when binding the javascript use a selector which looks for that class and only binds to elements with that special class.

How to get selected text from DevTools code editor?

I'm trying to get selected text from codeeditor of DevTools. I can get selectionInfo in onSelectionChanged handler, but I dont know how to get text.
Also how to get selectionInfo (current selection) before onSelectionChanged fired?
chrome.devtools.panels.sources.createSidebarPane(
"title",
function(sidebar) {
function update(selectionInfo) {
//alert([selectionInfo.url, selectionInfo.startLine, selectionInfo.endLine, selectionInfo.startColumn, selectionInfo.endColumn]);
sidebar.setObject(JSON.parse(JSON.stringify(selectionInfo)));
// How to extract text using data from selectionInfo ???
}
update(/*selectionInfo should be there*/);
chrome.devtools.panels.sources.onSelectionChanged.addListener(update);
}
);
The callback of chrome.devtools.panels.elements.onSelectionChanged.addListener doesn't take any argument, cf the API documentation. That means that your selectionInfo will always be undefined.
To get the selected element, you can use the $0 variable. Your code would therefore look like this:
chrome.devtools.panels.elements.createSidebarPane(
"title",
function(sidebar) {
function update() {
sidebar.setExpression("$0");
}
update();
chrome.devtools.panels.elements.onSelectionChanged.addListener(update);
}
);
Note: I replaced chrome.devtools.panels.sources, which doesn't exist, by chrome.devtools.panels.elements.

How to remove/unsubscribe listener from data table using YUI

I did subscribe an event on data table as follows (YUI data table):
myDataTable.subscribe("cellClickEvent", this.myDataTable.onEventShowCellEditor);
how can I achieve as follows?
If (condition)
show cell editor
else
remove or hide cell editor
Thanks in Adv.
onEventShowCellEditor is nothing really special, it simply calls method showCellEditor. So can you. Instead of setting a listener for the event and pass it straight through to onEventShowCellEditor put your own listener there instead and decide prior to calling showCellEditor:
myDataTable.subscribe('cellClickEvent', function (oArgs) {
if (condition) {
myDataTable.showCellEditor(oArgs.target);
} else {
...whatever
}
});

click to replace value, shift + click to append value using jquery

I have a list with items.
When I click any of these items, I copy its id-value into a form text-field.
Everytime I click, it replaces the value, which is correct by default. But what I would like to add, is a way for the user to hold down a key on their keyboard, and when they then click, they just .append whatever they just clicked into the same form field.
Here's my jQuery-code I'm using for the first/default scenario:
$(function(){
$('ul#filter-results li').click(function(){
var from = $(this).attr('id'); // get the list ID and
$('input#search').val(from+' ').keyup(); // insert into text-field then trigger the search and
$('input#search').focus(); // make sure the field is focused so the user can start typing immediately
});
});
Is there a way to implement some sort of keyboard key-listener?
Something like:
if (e.shiftKey){
.append('this text instead')
}
haven't tried out to see if shiftKey is even any valid name here
shiftKey is of one of the properties of the event object and is valid to be used. try this:
$(document).on('keyup click', function(e){
if (e.shiftKey) {
$('input#search').focus()
$('input#search').val(e.target.id)
}
})
DEMO
$('ul#filter-results').on('click', 'li', function(e) {
if(e.shiftKey) {
do something;
} else {
do something else;
}
});
There is a jQuery plugin for extended click.
You could try that or see how they have done it and implement it yourself.
ExtendedClick plugin
Hope this helps.
This is what I ended up with:
I switched over to altKey because shiftKey marked a lot of text when I clicked.
Didn't do anything besides it doesn't look good...
$(function(){
$('ul#filter-results li').click(function(e){
var text = $(this).attr('id'); // get the ID
var input = $('#search'); // form field to insert text into
if (e.altKey){ input.val(input.val()+', '+text+' ').keyup(); } // fetch whatever is already there, and add some more
else { input.val(text+' ').keyup(); } // just replace whatever is already there
$('#search').focus();
});
});
Thanks for good suggestions...

Getting the dijit for a typeAhead in XPages

I want to be able to add an onBlur/onkeypress/onChange events to all TypeAhead fields on the form rather than have a developer select every one in the Designer client. The only thing I cannot get a handle on is the onChange event.
When the user selects something in the TypeAhead the onChange event is triggered when adding the code directly to the event in the Domino Designer - so I should be able to replicate that capability with code.
If my typeAhead field is called inputText2 I thought I would be able to do the following
var widget = dojo.byId("#{id:inputText2}")
dojo.connect(widget, 'onChange', function (){
alert('1')
});
However this doesn't appear to work...
I tried lowercase onchange
var widget = dojo.byId("#{id:inputText2}")
dojo.connect(widget, 'onchange', function (){
alert('1')
});
no luck there either
I tried
var widget = dijit.byId("#{id:inputText2}");
but that failed to event select the element entirely
So what do I need to do to trigger the onchange event when selecting an option in the typeAhead?
I found a solution.....not ideal but it worked for the moment - not generic though, but a start
Copying the way XPages does it....add this to the page
function view__id1__id2__id31__id50_clientSide_onchange(thisEvent) {
alert('me')
}
and then
dojo.addOnLoad(function(){
XSP.addOnLoad(function() {
XSP.attachEvent("X1","view:_id1:_id2:_id31:inputText2", "onchange", view__id1__id2__id31__id50_clientSide_onchange, false, 2);
});
});
});
X1 must be unique but everything else can be calculated
Thanks to Serdar Basegmez

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