I'm having a look at Vue.js with a view to simplifying an application which is starting to get a bit too complex with jQuery. I want to utilise the data binding so that the state of an 'Order' object automatically enables or disables certain buttons (e.g., I want the submit button to be automatically disabled unless an order, containing items, exists). I have something which partly works, with this declaration:
var content = new Vue({
el: '#content',
computed: {
orderExists: function () {
return (shopOrder != null && !isEmpty(shopOrder.items));
}
}
});
I use it in a button like this:
<button type="button" id="btnDisplay" v-bind:disabled="!orderExists">Show Selected</button>
On page load, the buttons using this technique are indeed enabled/disabled correctly. However, when I add items to the order object, thereby changing its state, I'm not seeing any update in the buttons' states - they should be being enabled.
I assume I'm misunderstanding something basic about how this works with Vue.js, as I've only spent a couple of hours with it, so any help would be appreciated.
Hmmm why not pass the property as reactive data?
You can do something like:
...
computed: {
orderExists: function () {
this.disabled = (shopOrder != null && !isEmpty(shopOrder.items));
}
}
Fiddle.
DP: the example is in Vue 2
The issue is that Vue has to manage your data objects in order to set them up in a way where it can observe the changes to them (i.e. be made reactive). This is done by specifying the data option to your Vue creation. Something like:
data: {
shopOrder: null
}
Then update your code like this:
orderExists: function () {
return (this.shopOrder != null && !isEmpty(this.shopOrder.items));
}
And of course at some point you need to set this.shopOrder to a valid order object.
Related
I'm coding an app for managing shift work. The idea is pretty simple: the team is shared between groups. In those groups are specific shifts. I want to get something like that:
Group 1
- shift11
- shift12
- shift13
Group 2
- shift21
- shift22
- shift23
I already made a couple of tests, but nothing is really working as I would like it to: everything reactive, and dynamic.
I'm using vue.js, firestore (and vuefire between them).
I created a collection "shiftGroup" with documents (with auto IDs) having fields "name" and "order" (to rearrange the display order) and another collection "shift" with documents (still auto IDs) having fields "name", "order" (again to rearrange the display order, inside the group) and "group" (the ID of the corresponding shiftGroup.)
I had also tried with firestore.References of shifts in groups, that's when I was the closest to my goal, but then I was stuck when trying to sort shifts inside groups.
Anyway, with vuefire, I can easily bind shiftGroup like this:
{
data () {
return {
shiftGroup: [], // to initialize
}
},
firestore () {
return {
shiftGroup: db.collection('shiftGroup').orderBy('order'),
}
},
}
Then display the groups like this:
<ul>
<li v-for="(group, idx) in shiftGroup" :key="idx">{{group.name}}</li>
</ul>
So now time to add the shifts...
I thought I could get a reactive array of shifts for each of the groups, like that:
{
db.collection('shift').where('group', '==', group.id).orderBy('order').onSnapshot((querySnapshot) => {
this.shiftCollections[group.id] = [];
querySnapshot.forEach((doc) => {
this.shiftCollections[group.id].push(doc.data());
});
});
}
then I'd call the proper list like this:
<ul>
<li v-for="(group, idx) in shiftGroup" :key="idx">
{{group.name}}
<ul>
<li v-for="(shift, idx2) in shiftCollections[group.id]" :key="idx1+idx2">{{shift.name}}</li>
</ul>
</li>
</ul>
This is very bad code, and actually, the more I think about it, the more I think that it's just impossible to achieve.
Of course I thought of using programmatic binding like explained in the official doc:
this.$bind('documents', documents.where('creator', '==', this.id)).then(
But the first argument has to be a string whereas I need to work with dynamic data.
If anyone could suggest me a way to obtain what I described.
Thank you all very much
So I realize this is an old question, but it was in important use case for an app I am working on as well. That is, I would like to have an object with an arbitrary number of keys, each of which is bound to a Firestore document.
The solution I came up with is based off looking at the walkGet code in shared.ts. Basically, you use . notation when calling $bind. Each dot will reference a nested property. For example, binding to docs.123 will bind to docs['123']. So something along the lines of the following should work
export default {
name: "component",
data: function () {
return {
docs: {},
indices: [],
}
},
watch: {
indices: function (value) {
value.forEach(idx => this.$bind(`docs.${idx}`, db.doc(idx)))
}
}
}
In this example, the docs object has keys bound to Firestore documents and the reactivity works.
One issue that I'm trying to work through is whether you can also watch indices to get updates if any of the documents changes. Right now, I've observed that changes to the Firestore documents won't trigger a call to any watchers of indices. I presume this is related to Vue's reactivity, but I'm not sure.
I'm building an auto-complete menu in Vue.js backed by Firebase (using vue-fire). The aim is to start typing a user's display name and having match records show up in the list of divs below.
The template looks like this:
<b-form-input id="toUser"
type="text"
v-model="selectedTo"
#change="searcher">
</b-form-input>
<div v-on:click="selectToUser(user)" class="userSearchDropDownResult" v-for="user in searchResult" v-if="showSearcherDropdown">{{ user.name }}</div>
Upon clicking a potential match the intention is to set the value of the field and clear away the list of matches.
Here is the code portion of the component:
computed: {
/* method borrowed from Reddit user imGnarly: https://www.reddit.com/r/vuejs/comments/63w65c/client_side_autocomplete_search_with_vuejs/ */
searcher() {
let self = this;
let holder = [];
let rx = new RegExp(this.selectedTo, 'i');
this.users.forEach(function (val, key) {
if (rx.test(val.name) || rx.test(val.email)) {
let obj = {}
obj = val;
holder.push(obj);
} else {
self.searchResult = 'No matches found';
}
})
this.searchResult = holder;
return this.selectedTo;
},
showSearcherDropdown() {
if(this.searchResult == null) return false;
if(this.selectedTo === '') return false;
return true;
}
},
methods: {
selectToUser: function( user ) {
this.newMessage.to = user['.key'];
this.selectedTo = user.name;
this.searchResult = null;
}
}
Typeahead works well, on each change to the input field the searcher() function is called and populates the searchResult with the correct values. The v-for works and a list of divs is shown.
Upon clicking a div, I call selectToUser( user ). This correctly reports details from the user object to the console.
However, on first click I get an exception in the console and the divs don't clear away (I expect them to disappear because I'm setting searchResults to null).
[Vue warn]: Error in event handler for "change": "TypeError: fns.apply is not a function"
found in
---> <BFormInput>
<BFormGroup>
<BTab>
TypeError: fns.apply is not a function
at VueComponent.invoker (vue.esm.js?efeb:2004)
at VueComponent.Vue.$emit (vue.esm.js?efeb:2515)
at VueComponent.onChange (form-input.js?1465:138)
at boundFn (vue.esm.js?efeb:190)
at invoker (vue.esm.js?efeb:2004)
at HTMLInputElement.fn._withTask.fn._withTask (vue.esm.js?efeb:1802)
If I click the div a second time then there's no error, the input value is set and the divs disappear.
So I suspect that writing a value to this.selectedTo (which is also the v-model object for the element is triggering a #change event. On the second click the value of doesn't actually change because it's already set, so no call to searcher() and no error.
I've noticed this also happens if the element loses focus.
Question: how to prevent an #change event when changing v-model value via a method?
(other info: according to package.json I'm on vue 2.5.2)
On:
<b-form-input id="toUser"
type="text"
v-model="selectedTo"
#change="searcher">
The "searcher" should be a method. A method that will be called whenever that b-component issues a change event.
But looking at your code, it is not a method, but a computed:
computed: {
searcher() {
...
},
showSearcherDropdown() {
...
}
},
methods: {
selectToUser: function( user ) {
...
}
}
So when the change event happens, it tries to call something that is not a method (or, in other words, it tries to call a method that doesn't exist). That's why you get the error.
Now, since what you actually want is to update searcher whenever this.selectedTo changes, to get that, it is actually not needed to have that #change handler. This is due to the code of computed: { searcher() { already depending on this.selectedTo. Whenever this.selectedTo changes, Vue will calculate searcher again.
Solution: simply remove #change="searcher" from b-form. Everything else will work.
#acdcjunior, thanks for your answer.
Of course just removing the reference to searcher() just means no action is taken upon field value change so the field won’t work at all.
Moving the searcher() function into methods: {} instead of computed: {} means that it will be called on an input event and not a change even (another mystery but not one for today). A subtle difference that takes away the typeahead feature I’m aiming at.
However, it did make me remember that the result of computed: {} functions are cached and will be re-computed when any parameters change. In this case I realised that the searcher() function is dependent upon the this.selectedTo variable. So when the selectToUser() function sets this.selectedTo it triggers another call to searcher().
Fixed now. In case anyone has a similar problem in the future, I resolved this by turning to old fashioned semaphore by adding another variable.
var userMadeSelection: false
Now, searcher() begins with a check for this scenario:
computed: {
searcher() {
if(this.userMadeSelection) {
this.userMadeSelection = false;
return this.selectedTo;
}
…
and then in selectToUser():
this.userMadeSelection = true;
This was originally posted on discuss.emberjs.com. See:
http://discuss.emberjs.com/t/what-is-the-proper-use-of-store-filter-store-find-for-infinite-scrolling/3798/2
but that site seems to get worse and worse as far as quality of content these days so I'm hoping StackOverflow can rescue me.
Intent: Build a page in ember with ember-data implementing infinite scrolling.
Background Knowledge: Based on the emberjs.com api docs on ember-data, specifically the store.filter and store.find methods ( see: http://emberjs.com/api/data/classes/DS.Store.html#method_filter ) I should be able to set the model hook of a route to the promise of a store filter operation. The response of the promise should be a filtered record array which is a an array of items from the store filtered by a filter function which is suppose to be constantly updated whenever new items are pushed into the store. By combining this with the store.find method which will push items into the store, the filteredRecordArray should automatically update with the new items thus updating the model and resulting in new items showing on the page.
For instance, assume we have a Questions Route, Controller and a model of type Question.
App.QuestionsRoute = Ember.Route.extend({
model: function (urlParams) {
return this.get('store').filter('question', function (q) {
return true;
});
}
});
Then we have a controller with some method that will call store.find, this could be triggered by some event/action whether it be detecting scroll events or the user explicitly clicking to load more, regardless this method would be called to load more questions.
Example:
App.QuestionsController = Ember.ArrayController.extend({
...
loadMore: function (offset) {
return this.get('store').find('question', { skip: currentOffset});
}
...
});
And the template to render the items:
...
{{#each question in controller}}
{{question.title}}
{{/each}}
...
Notice, that with this method we do NOT have to add a function to the store.find promise which explicitly calls this.get('model').pushObjects(questions); In fact, trying to do that once you have already returned a filter record array to the model does not work. Either we manage the content of the model manually, or we let ember-data do the work and I would very much like to let Ember-data do the work.
This is is a very clean API; however, it does not seem to work they way I've written it. Based on the documentation I cannot see anything wrong.
Using the Ember-Inspector tool from chrome I can see that the new questions from the second find call are loaded into the store under the 'question' type but the page does not refresh until I change routes and come back. It seems like the is simply a problem with observers, which made me think that this would be a bug in Ember-Data, but I didn't want to jump to conclusions like that until I asked to see if I'm using Ember-Data as intended.
If someone doesn't know exactly what is wrong but knows how to use store.push/pushMany to recreate this scenario in a jsbin that would also help too. I'm just not familiar with how to use the lower level methods on the store.
Help is much appreciated.
I just made this pattern work for myself, but in the "traditional" way, i.e. without using store.filter().
I managed the "loadMore" part in the router itself :
actions: {
loadMore: function () {
var model = this.controller.get('model'), route = this;
if (!this.get('loading')) {
this.set('loading', true);
this.store.find('question', {offset: model.get('length')}).then(function (records) {
model.addObjects(records);
route.set('loading', false);
});
}
}
}
Since you already tried the traditional way (from what I see in your post on discuss), it seems that the key part is to use addObjects() instead of pushObjects() as you did.
For the records, here is the relevant part of my view to trigger the loadMore action:
didInsertElement: function() {
var controller = this.get('controller');
$(window).on('scroll', function() {
if ($(window).scrollTop() > $(document).height() - ($(window).height()*2)) {
controller.send('loadMore');
}
});
},
willDestroyElement: function() {
$(window).off('scroll');
}
I am now looking to move the loading property to the controller so that I get a nice loader for the user.
I have 3 routes: items/one, items/two, and items/three and they're all pointing to 'items' vm/view.
in the items.js activate function, I'm checking the url, and based on that, I'm changing a filter:
function activate(r) {
switch (r.routeInfo.url) {
case 'items/one': vm.filterType(1); break;
case 'items/two': vm.filterType(2); break;
case 'items/three': vm.filterType(3); break;
}
return init(); //returns a promise
}
The items view has a menu with buttons for one, two, and three.
Each button is linked to an action like this:
function clickOne() {
router.navigateTo('#/items/one');
}
function clickTwo() {
router.navigateTo('#/items/two');
}
function clickThree() {
router.navigateTo('#/items/three');
}
this all works and I get the right filter on the view. However, I've noticed that if I'm on 'one', and then go to 'two', the ko-bound variables update in 'real-time', that is, as they're changing, and before the activate promise resolves, which causes the transition to happen twice (as the data is being grabbed, and after the activate function returns).
This only happens in this scenario, where the view and viewmodel are the same as the previous one. I'm aware that this is a special case, and the router is probably handling the loading of the new route with areSameItem = true. I could split the VMs/Views into three and try to inherit from a base model, but I was hoping for a simpler solution.
I was able to solve the issue by simply removing the ko bindings before navigation using ko.cleanNode() on the items containing div.
Assuming that in your parent view you've a reference to router.activeItem with a transition e.g.
<!--ko compose: {model: router.activeItem,
afterCompose: router.afterCompose,
transition: 'entrance'} -->
<!--/ko-->
then the entrance transition happens on every route you've setup to filter the current view.
But this transition should probably only happen on first time visit and from that point on only the view should be updated with the filtered data. One way to accomplish that would be to setup an observable filterType and use filterType.subscribe to call router.navigateTowith the skip parameter.
Something along the line:
var filterType = ko.observable();
filterType.subscribe(function (val) {
// Create an entry in the history but don't activate the new route to prevent transition
// router plugin expects this without leading '/' dash.
router.navigateTo(location.pathname.substring(1) + '#items/' + filterType(), 'skip');
activate();
});
Please note that the router plugin expects skipRouteUrl without leading / slash to compare the context.path. https://github.com/BlueSpire/Durandal/blob/master/App/durandal/plugins/router.js#L402
Your experience might be different.
Last in order to support deep linking in activate:
function activate(routerdata) {
// deep linking
if (routerdata && routerdata.filterType && (routerdata.filterType !== filterType() ) ) {
filterType(routerdata.filterType);
}
return promise;
};
I am rather new to sencha touch, I've done a lot of research and tutorials to learn the basics but now that I am experimenting I have run into a problem that I can't figure out.
I have a basic DataList which gets its data from a store which displays in a xtemplate.
Within this template I have created a member function which requires store field data to be parsed as a parameter.
I would like to make a thumbnail image (that's source is pulled from the store) execute the member function on click/tap.
I can't find any information on this within the docs, does anyone know the best way to go about this?
Here is a code example (pulled from docs as I can't access my actual code right now).
var tpl = new Ext.XTemplate(
'<p>Name: {name}</p>'
{
tapFunction: function(name){
alert(name);
}
}
);
tpl.overwrite(panel.body, data);
I want to make the paragraph clickable which will then execute the tapFunction() member function and pass the {name} variable.
Doing something like onclick="{[this.tapFunction(values.name)]} " does not seem to work.
I think functions in template are executed as soon as the view is rendered so I don't think this is the proper solution.
What I would do in your case is :
Add a unique class to your < p > tag
tpl : '<p class="my-p-tag">{name}</p>'
Detect the itemtap event on the list
In your dataview controller, you add an tap event listener on your list.
refs: {
myList: 'WHATEVER_REFERENCE_MATCHES_YOUR_LIST'
},
control: {
myList: {
itemtap: 'listItemTap'
}
}
Check if the target of the tap is the < p > tag
To do so, implement your listItemTap function like so :
listItemTap: function(list,index,target,record,e){
var node = e.target;
if (node.className && node.className.indexOf('my-p-tag') > -1) {
console.log(record.get('name'));
}
}
Hope this helps