My situation
I have a BIG list of people which all have their own profile pic and information. All items have some CSS3 styling/animations.
Im using:
<li ng-repeat="person in people">
Where people is an array with over 150 objects from an external JSON file that all have to show on the same page.
The page loads/renders slowly, and its not because of the $http GET function that gets the JSON data with people (which only takes about 100ms), but the rendering of the page and seemingly the rendering of all the css3 styling applied to each item (if i turn my CSS off it gets much faster).
My main problem
I can live with the page rendering slowly but what i really want is to detect whenever my heavy page has loaded its content in order to start and stop a loading indicator. Ive tried making a directive like this:
directive("peopleList", function () {
return function (scope, element, attrs) {
scope.$watch("people", function (value) {
var val = value || null;
console.log("Loading started");
if (val){
console.log("Loading finished");
}
});
};
});
And put this directive on the wrapper div that is loading my list of people. But the loading appears to stop whenever my object with JSON data has been filled, which only takes around 100ms, but the actual visual rendering of the page takes more like 4-5s.
Ive also tried solutions like http://jsfiddle.net/zdam/dBR2r/ but i get the same result there.
What i need
When i navigate through my pages (which all have the same kind of lists) i need something that tells me whenever the page has fully loaded and is visible for the user so that i know when to hide my loading indicator.
Try adding this directive -- the magic is in the link function:
directives
.directive('onFinishRender', function ($timeout) {
return {
restrict: 'A',
link: function (scope, element, attr) {
if (scope.$last === true) {
scope.$evalAsync(attr.onFinishRender);
}
}
}
});
Add a loader as the first item:
<li ng-show="!isDoneLoading">
<div class="loading">Loading...</div>
</li>
Then in your li, add this:
<li ng-repeat="..." on-finish-render="isDoneLoading = true;"> ... </li>
Related
I have a parent/child component setup where the parent is loading data from the server and passing it down to children via props. In the child I would like to instantiate a jQuery calendar with some of the data it receives from the parent.
In order to wait for the data before setting up the calendar, I broadcast an event in the parent that I have an event listener setup for in the child.
The listener is being fired in the child but if I this.$log('theProp'), it's undefined. However, if I inspect the components with the VueJs devtools, the parent/child relationship is there and the child has received the prop in the meantime.
The prop is defined on the child as a dynamic prop :the-prop="theProp". Since the child does receive the prop in the end, I'm assuming my setup is correct but there seems to be some sort of delay. The parent sets the props in the return function of the ajax call and again: it's working, just with a slight delay it seems.
I also tried registering a watch listener on the prop in the child so I could setup the calendar then and be sure that the prop is there. However, the watch listener fires, but this.$log('theProp') is still undefined.
If I pass the data along with the the broadcast call, like this.$broadcast('dataLoaded', theData) the child receives it just fine. But it seems wrong to do it that way as I'm basically building my own prop handler.
I'm not posting any code because the components are rather large and the VueJs devtools are telling me the parent/child situation is working.
Am I missing some information? Is there a slight delay between setting a value in the parent and the child receiving it? What would be the proper way to wait for parent data in the child?
Normally, when you're just rendering the data out into the template, the timing doesn't matter so much since the data is bound to the template. But in this case, I really need the data to be there to setup the calendar or it will be wrong.
Thanks.
edit 1: here's a jsfiddle: https://jsfiddle.net/dr3djo0u/1/
It seems to confirm that the data is not available immediately after the broadcast. However, the watcher does work, though I could almost swear that sometimes this.$log('someData') returned undefined when I setup that testcase.
But I guess my problem might be somewhere else, I'll have a look tonight, don't have the project with me right now.
edit 2: did some more tests. My problem was that a) event listeners do not seem to receive the data instantly and b) I was also trying to init the calendar in the route.data callback if someData was already around (e.g. when coming from parent), but that route callback is called before the component is ready, so it wasn't working there either.
My solution is now this:
// works when the child route is loaded directly and parent finishes loading someData
watch: {
someData() {
this.initCalendar();
}
},
// works when navigating from parent (data already loaded)
ready() {
if (this.someData && this.someData.length) {
this.initCalendar()
}
}
As far as I know, you should not need events to pass data from parent to child.
All you need is, in the child component: props: ['theProp']
And when using the child component in the parent: <child :theProp="someData"></child>
Now, wherever in the parent you change someData, the child component will react accordingly.
You don't need events, you don't need "watch", you don't need "ready".
For example: after an AJAX call, in the parent's "ready", you load some data:
// at the parent component
data: function () {
return {
someData: {}
}
},
ready: function () {
var vm = this;
$.get(url, function(response) {
vm.someData = response;
});
}
Now, you do not need anything else to pass the data to the child. It is already in the child as theProp!
What you really need to do is to have, in the child, something which reacts to data changes on its own theProp property.
Either in the interface:
<div v-if="theProp.id > 0">
Loaded!
</div>
Or in JavaScript code:
// at the child component
computed: {
// using a computed property based on theProp's value
awesomeDate: function() {
if (!this.theProp || (this.theProp.length === 0)) {
return false;
}
if (!this.initialized) {
this.initCalendar();
}
return this.theProp.someThing;
}
}
Update 1
You can also, in the parent, render the child conditionally:
<child v-if="dataLoaded" :theProp="someData"></child>
Only set dataLoaded to true when the data is available.
Update 2
Or maybe your issue is related to a change detection caveat
Maybe you're creating a new property in an object...
vm.someObject.someProperty = someValue
...when you should do...
vm.$set('someObject.someProperty', someValue)
...among other "caveats".
Update 3
In VueJS 2 you are not restricted to templates. You can use a render function and code the most complex rendering logic you want.
Update 4 (regarding OP's edit 2)
Maybe you can drop ready and use immediate option, so your initialization is in a single place:
watch: {
someData: {
handler: function (someData) {
// check someData and eventually call
this.initCalendar();
},
immediate: true
}
}
It's because tricky behavior in Vue Parent and Child lifecycle hooks.
Usually parent component fire created() hook and then mount() hook, but when there are child components it's not exactly that way: Parent fires created() and then his childs fire created(), then mount() and only after child's mount() hooks are loaded, parent loads his mount() as explained here. And that's why the prop in child component isn't loaded.
Use mounted() hook instead created()
like that https://jsfiddle.net/stanimirsp5/xnwcvL59/1/
Vue 3
Ok so I've spent like 1.5h trying to find out how to pass prop from parent to child:
Child
<!-- Template -->
<template>
<input type="hidden" name="_csrf_token" :value="csrfToken">
<span>
{{ csrfToken }}
</span>
</template>
<!-- Script -->
<script>
export default {
props: [
"csrfToken"
]
}
</script>
Parent
<!-- Template -->
<template>
<form #submit.prevent="submitTestMailForm" v-bind:action="formActionUrl" ref="form" method="POST">
...
<CsrfTokenInputComponent :csrf-token="csrfToken"/>
...
</form>
</template>
<!-- Script -->
<script>
...
export default {
data(){
return {
...
csrfToken : "",
}
},
methods: {
/**
* #description will handle submission of the form
*/
submitTestMailForm(){
let csrfRequestPromise = this.getCsrfToken();
let ajaxFormData = {
receiver : this.emailInput,
messageTitle : this.titleInput,
messageBody : this.bodyTextArea,
_csrf_token : this.csrfToken,
};
csrfRequestPromise.then( (response) => {
let csrfTokenResponseDto = CsrfTokenResponseDto.fromAxiosResponse(response);
this.csrfToken = csrfTokenResponseDto.csrToken;
this.axios({
method : "POST",
url : SymfonyRoutes.SEND_TEST_MAIL,
data : ajaxFormData,
}).then( (response) => {
// handle with some popover
})
});
},
/**
* #description will return the csrf token which is required upon submitting the form (Internal Symfony Validation Logic)
*/
getCsrfToken(){
...
return promise;
}
},
components: {
CsrfTokenInputComponent
}
}
</script>
Long story short
This is how You need to pass down the prop to child
<CsrfTokenInputComponent :csrf-token="csrfToken"/>
NOT like this
<CsrfTokenInputComponent csrf-token="csrfToken"/>
Even if my IDE keep me telling me yeap i can navigate with that prop to child - vue could not bind it.
solution (testing ok)
In child component just using the props data, no need to re-assignment props's values to data, it will be cause update bug!
vue child component props update bug & solution
https://forum.vuejs.org/t/child-component-is-not-updated-when-parent-component-model-changes/18283?u=xgqfrms
The problem is not how to pass data with props, but rather how to do two things at almost the same time.
I have an user account component that can edit users (with an user id) and add users (without id).
A child component shows checkboxes for user<->company assignments, and needs the user id to prepare API calls when the user account is saved.
It is important that the child component shows before saving the user account, so that things can be selected before the user is saved and gets an id.
So it has no user id at first: the id is passed to the child component as 'null'.
It updates when the user is stored and gets an id.
But at this point, it takes a very short time for the child to get the new id into its model.
If you call a function in the child component that relies on data that was just changing, it might happen that the function executes before the data is updated.
For cases like this, nextTick() is your friend.
import { nextTick } from 'vue';
...
saveAccount() {
axios.post(URL, this.userModel).then((result)) {
// our model gets an id when persisted
this.userModel.id=result.data.id;
nextTick( () => {
this.$refs.childComponent.doSomething();
});
}
}
The default Accounts-UI widget takes a while to load. I want to check on the client when it is ready, so that I can perform some DOM manipulations on it afterwards. I am currently using a timer like so:
Template.sign_in_modal.onRendered(function (){
Tracker.afterFlush(function () {
Meteor.setTimeout(function () {
$('a#login-sign-in-link').click();
$('a#login-name-link').click();
$('a.login-close-text').remove();
}, 100);
});
});
The above hack works locally (probably because it loads faster) but not when I push to saturnapi.com. I just want it to be expanded by default as shown below. Is there a way to ensure the UI widget is fully loaded via a template helper or otherwise make it expanded by default?
I would suggest checking when the <a id="login-sigin-in-link"></a> is added to the DOM. This could be verified by checking $('a#login-sign-in-link').length. If the element is on the DOM do your manipulation.
However if it is not just check again in a few milliseconds. I would suggest using setInterval().
See below for the complete solution:
Template.sign_in_modal.onRendered(function (){
var setIntervalId = Meteor.setInterval(function() {
if($('a#login-sign-in-link').length) {
$('a#login-sign-in-link').click();
$('a.login-close-text').remove();
Meteor.clearInterval(setIntervalId);
}
}, 100);
});
Template.sign_in_modal.onDestroyed(function() {
$('.modal-backdrop.fade.in').remove();
});
Some may think that using loginButtons.onRendered(function(){}); is a good way to verify if the element has been added to the DOM, but it is not. If you try to do the same DOM manipulation in onRendered, it will throw an afterFlush error. The onRendered function has been extremely misleading.
I have a sortable list.
<template name="the_playlist">
{{#each main_list}}
<li id="{{index}}" class="list_element">
<div class="next_song">...</div>
<div class="destroy">...</div>
<div class="element_style">{{song_title}}</div>
</li>
{{/each}}
</template>
And this is the main_list that it prints from.
Template.the_playlist.main_list = function(){
//if ret is valid, it will have a songs member
var ret = Links.find().fetch()[0];
if (typeof ret == 'undefined'){
ret = []
}
else {
ret = Links.find().fetch()[0].songs;
}
return ret;
}
And I am using the sortable plugin and more importantly its update callback which updates everytime the user changes a position the list or an element is added to the list.
$(function() {
$( "#playlist" ).sortable({
update: function(){
Template.list.updateList(); //MODIFIES DB CONTENTS, AND MAIN_LIST's VALUES CHANGE
}});
$( "#playlist" ).disableSelection();
});
*The problem: * If a page already has list elements when it's loaded, for one time only, I would like to add a class that hides (.addClass("hide")) each of the next_song elements that are on the page at that time. This *will work only until main_list changes* by a call to Template.list.updateList above, after which automagically, the added class will disappear - most likely due to the re-rendering that is occuring since the main_list depends on the db changes.
The following in the JQuery snippet I use to try and accomplish this.
$("#playlist li .next_song").each(function(){
$(this).addClass("hide_song");
})
Here is a demo. Try plugging in the above JQUery code into the console. and then move the list elements around to see the problem.
Can you not just determine whether that will be the case in a helper function?
Template.the_playlist.helpers({
'list_elements_exist': function() {
return (!!$('#playlist li').length);
}
}
Then you can just insert the logic straight into the template:
<div class="next_song{{#if list_elements_exist}} hide_song{{/if}}">...</div>
To be honest, I'm not 100% sure that this will float with reactivity depending on the structure of your app. If it doesn't work properly, I'd introduce a new session boolean, list_elements, the value of which is returned by the helper function above. It should be fairly easy to update its value in event handlers or created callbacks to keep it tracking whether there are any items in the list or not, and this will guarantee the list renders as required regardless of other dependencies changing.
I work on a Visual Studio 2012 MVC4 Project with the Durandal template. In this template, the shell.js page gives us a quite simple menu solution where every elements are located on top. Personally I need something different. For that purpose, I have a javascript file named dropdown.js which allows me to show/hide sub menus. It works pretty well in a standard project but I was not able to do it working with the durandal template.
Here is what I try:
I added a reference to the dropdown.js script in the Index.chtml:
<script src="~/Scripts/dropdown.js"></script>
Then in the shell.html page, I would like to use it like this:
<li class="dropdown" data-role="dropdown">
...
...
</li>
Here is a little portion of the dropdown.js:
$(function () {
alert('XXXX');
$('[data-role="dropdown"]').each(function () {
alert('YYYY');
$(this).Dropdown();
})
})
As you can see, each element decorated with the 'dropdown' class should have been catched. It doesn't work with durandal. I placed some alert boxes to check it. The alert 'XX' is showed but the alert 'YY' is never showed.
I searched a bunch of hours without success.
Any idea?
Check out the life cycle events tha tyou can tap into for Durandal here
viewAttached may help since you can tap into when the view and dom are ready.
I think the problem is that when the dropdown.js function is executed before the menu renders and because of that the jquery selector doesn't catch any list item.
I think that your best option is to make a knockout binding to transform your list items in dropdowns.
The binding would look something like:
ko.bindingHandlers.dropdown= {
init: function (element, valueAccessor, allBindingsAccessor) {
$(element).Dropdown();
},
update: function (element, valueAccessor) {
}
};
And in the view:
<li class="dropdown" data-bind="dropdown : {}">
...
...
</li>
I have a page for an internal app that displays document images streamed from a document storage system using a web service. The problem I am having is that when a user does their search they may get hundreds of hits, which I have to display on one large page so they can print them all. This works fine in Firefox, but in IE it stops loading the images after a while so I get a hundred or so displayed and the rest just have the broken image symbol. Is there a setting somewhere that I can change this timeout?
If the issue is indeed a timeout, you might be able to work around it by using a "lazy load" script and adding new images to the document only after existing images have loaded.
There are a lot of ways to do this, but here's a simple example I threw together and tested. Instead of this:
<img src="image001.jpg" />
<img src="image002.jpg" />
<img src="image003.jpg" />
<img src="image004.jpg" />
<!-- Etc etc etc -->
You could do this:
<div id="imgsGoHere">
</div>
<script type="text/javascript">
function crossBrowserEventAttach(objectRef, eventName, functionRef)
{
try {
objectRef.addEventListener(eventName, functionRef, false);
}
catch(err) {
try {
objectRef.attachEvent("on" + eventName, functionRef);
}
catch(err2) {
// event attachment failed
}
}
}
function addImageToPage()
{
var newImageElement = document.createElement("img");
newImageElement.src = imageArray[nextImageNumber];
var targetElement = document.getElementById("imgsGoHere");
targetElement.appendChild(newImageElement);
nextImageNumber++;
if (nextImageNumber < imageArray.length) {
crossBrowserEventAttach(newImageElement, "load", addImageToPage);
crossBrowserEventAttach(newImageElement, "error", addImageToPage);
}
}
var nextImageNumber = 0;
var imageArray = new Array();
imageArray[imageArray.length] = "image001.jpg";
imageArray[imageArray.length] = "image002.jpg";
imageArray[imageArray.length] = "image003.jpg";
// .
// .
// .
// Snip hundreds of rows
// .
// .
// .
imageArray[imageArray.length] = "image999.jpg";
addImageToPage();
</script>
Each image is added to the page only after the previous image loads (or fails to load). If your browser is timing out, I think that will fix it.
Of course, the problem might actually not be a timeout, but rather that you're running out of memory/system resources and IE is giving up. Or there might be an IE DOM limitation like Sra said.
No final solution, but some hints...
I think the ie Dom hangs up. I,ve seen this in other cases. I needed simply to show the images and used a js which loads the image the time they came into focus, but that want work if you directly hit print I think. Can you use the new css ability to store imagedata directly instead of links. That should solve your problem. I am not quite sure but I think it is supported since ie 7
My guess is that you have to work around the IE setting, the easiest way to do it is simply not showing images that are not loaded or replacing them with a default image:
your html:
<img src="http://domain.com/image.jpg" />
your js:
$('img').load(function(){
// ... loaded
}).error(function(){
// ... not loaded, replace
$(this).attr('src','/whatever/default.jpg');
// ... not loaded, hide
$(this).hide();
});
That is a problem with microsoft. Unfortunately, this is a setting that would have to be changed on every single computer, as there is no remote way to alter it. To change it on your computer, try opening regedit and adding the RecieveTimeout DWORD with a Value of (#of minutes)*6000. Hope this helps-CodeKid1001
Edit: Sorry about that, I forgot to put in the file path:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\InternetSettings
I used something similar to laod HD pictures as a background using ASP Pages
But i used jQuery to handle the images and its loading. This is a sample for 1 image but with a bit of tweaking you can load dynamically
myImage = new Image();
$(myImage).load(function ()
{
$(this).hide(); //Stops the loading effect of large images. can be removed
$('.csBackground li').append(this); //Append image to where you need it
$(myImage).show();
}).attr('src', settings.images[0]) //I pass an array from ASP code behind so 0 can be 'i'
.error( function { checkImages(); } ) //try and relaod the image or something?
So instead of changing the timeout- just try and reload the images on error.
Otherwise i only found a solution that is client specific (HTTP Timeout)
http://support.microsoft.com/kb/813827