Ember question - still getting used to Ember, but making progress. Here's my issue: I have a template which references a component; the component contains a select element. The select element displays properly, and I want to update the contents of another select element based on the selection in the first element. However, I have not been able to capture the on change event of the first select element. Here is the component code containing the select:
{{view
"select"
content=types
value=selectedtType
selection=selectedtType
prompt="Select Type..."
}}
So I'm not sure how to reference the on change event in the component template, or where the function itself should go - the component's component.js file, or in the route.js file of the parent template. I've done much research on this, but haven't been able to make it work yet. Any help would be appreciated. Thanks.
Check this JSBin. In this example, I had my dependent select use a computed property as its content. This computed property's single dependent key is the value of the first select. If you are doing this with components, your component needs to take the computed property as the attribute that is the select views' content. Any time the first select changes, it will cause the computed property to recompute and thus update the content of the second select. Even in an example using components, this code would probably sit on the controller to keep your component generic enough that it simply takes a content for its select and displays it rather than controlling the display logic itself.
Other options, have a function that observes the first select value and updates a controller variable that is the second select's content. Now if you're example is more complicated in that the changing select's have different option.valuePath and option.labelPath, you can pass pass those values into your component as well.
Related
I have a contentEditable div where I want to allow users to type text, as well as insert input elements such as text boxes and dropdowns. The elements will be inserted where the cursor currently is, by allowing the user to click a button outside the editable div.
I got it working pretty well following this general example:
http://jsfiddle.net/jwvha/1/
which basically does a
document.selection.createRange().pasteHTML(html);
The problem is that it expects HTML to be passed into the function which inserts the element at cursor. For more complex things, I'd like to be able to insert Ember components with full html/js logic available, instead of trying to put all html/js into a string.
Is there a way to programmatically create a component AND insert it into a contentEditable element at cursor, while maintaining its functionality, such as actions, etc.
I'm on Ember 2.5 currently.
I think you could use a ember-cli plugin called ember-wormhole. What this component do is basically move the dom of you ember component to an html element that contains an id attribute.
e.g.
document.selection.createRange().pasteHTML('<div id="my-component-id"></div>');
use my-component-id to ember-wormhole destinantion attribute:
{{#ember-wormhole to="my-component-id"}}
{{my-component...}}
{{/ember-wormhole}}
Regarding that, you could do something like:
click() {
let componentId = 'my-component-id';
document.selection.createRange().pasteHTML(`<div id="${componentId}"></div>`);
this.get('components').pushObject(componentId); // components being an array
}
in your handlebars template:
{{#each components as |componentId|}}
{{#ember-wormhole to=componentId}}
{{my-component...}}
{{/ember-wormhole}}
{{/each}}
I have a contentEditable div where I want to allow users to type text, as well as insert input elements such as text boxes and dropdowns. The elements will be inserted where the cursor currently is, by allowing the user to click a button outside the editable div.
I got it working pretty well following this general example:
http://jsfiddle.net/jwvha/1/
which basically does a
document.selection.createRange().pasteHTML(html);
The problem is that it expects HTML to be passed into the function which inserts the element at cursor. For more complex things, I'd like to be able to insert Ember components with full html/js logic available, instead of trying to put all html/js into a string.
Is there a way to programmatically create a component AND insert it into a contentEditable element at cursor, while maintaining its functionality, such as actions, etc.
I'm on Ember 2.5 currently.
I think you could use a ember-cli plugin called ember-wormhole. What this component do is basically move the dom of you ember component to an html element that contains an id attribute.
e.g.
document.selection.createRange().pasteHTML('<div id="my-component-id"></div>');
use my-component-id to ember-wormhole destinantion attribute:
{{#ember-wormhole to="my-component-id"}}
{{my-component...}}
{{/ember-wormhole}}
Regarding that, you could do something like:
click() {
let componentId = 'my-component-id';
document.selection.createRange().pasteHTML(`<div id="${componentId}"></div>`);
this.get('components').pushObject(componentId); // components being an array
}
in your handlebars template:
{{#each components as |componentId|}}
{{#ember-wormhole to=componentId}}
{{my-component...}}
{{/ember-wormhole}}
{{/each}}
I have a mixin for Ember components, named in-view, the job of which is to request that that the element be brought in view. It is provided an attribute whose value is an piece of content to be brought into view, and if that attribute matches the component's content then I call scrollIntoView or the equivalent. The code looks something like this:
// calling template
{{#each items as |item|}}
{{my-item content=item inViewItem=inViewItem}}
}}
// mixins/in-view.js
scrollIntoView() {
if (this.get('content') === this.get('inViewItem'))
this.get('element').scrollIntoView();
}.on('didInsertElement')
// components/my-item/component.js
import InView from 'mixins/in-view';
export default Ember.Component.extend(InView,
This works fine. The question I have arises when I want to change the item in view. I can have the in-view mixin observe the inviewItem attribute:
}.on('didInsertElement').observes('inViewItem')
and this also works, but seems like a bit of a code smell.
In addition, my actual code structure is that there is a controller which knows which item is supposed to be in view, and then its template calls a my-item-list component which displays the scrollable div containing the item list, and that in turn calls the my-item component. This means I have to pass the inViewItem attribute from the controller down through two levels, as in
// resource/controller.js
inViewItem: something
// resource/template.js
{{my-item-list items=item inViewItem=inViewItem}}
// components/my-item-list/template.js
{{#each items as |item|}}
{{my-item content=item inViewItem=inViewItem}}
}}
I could avoid this by having the my-item template hard-wired to access the inViewItem attribute on the controller:
scrollIntoView() {
if (this.get('content') === this.get('controller.inViewItem'))
this.get('element').scrollIntoView();
}.on('didInsertElement')
but that's another code smell; I don't want to build this kind of dependency on a specific controller field into the mixin. Instead I could possibly pass the component the name of the controller attribute to watch, but this seems unduly clumsy, and it's tricky to observe an attribute whose name is variable. More importantly, I don't think this will work when controllers go away in 2.0.
What I want essentially is a way to "ping" or somehow send a message to a template. I know that in principle this violates the DDAU principle, but in this particular case what I need is exactly to somehow send an "action down"--an action telling the component to adjust itself to bring itself into view.
Of course, I could give up on the entire idea of the in-view mixin and simply have the controller dig down into the generated HTML to find the item to bring into view and issue the scrollIntoView on it directly. However, this seems to violate some principle of separation of concerns; the my-item template would no longer be in complete control of itself.
What is the recommended design pattern for this kind of case?
The solution here is to go the opposite direction that you have. Your component here is a localized scope, and the pain you are feeling is that your localized scope needs to access and mutate global state (the app's scroll position).
Some people use a scroll-service for keeping track of and mutating state, I've used several variations on that myself.
It sounds though like you're dealing with a scrollable list, perhaps a div, and that what item is in view isn't merely a function of page state, but programmatically may change. For instance, a new item has been inserted and you want to scroll the new item into view.
A plugin like jquery.scrollTo or similar (collectively "scroller") would be better for that than simply jumping to the new position as it preserves the user's contextual awareness to where they are on page.
With a scrollable div or list or similar, you might choose to have your top level component control scroll state. The scroll state is still localized in this case, but instead of being localized to each item it's been localized to the scrollable region as a whole, which is where it better belongs.
There are a number of patterns for list items to register themselves with a parent list-component. In a robust scenario, I might do so, but a quick and not very dirty approach is to do something wherein on didInsertElement the new child emits an action to the parent containing it's context, which the parent then uses to check if it's the active item and if so triggers the scrollTo.
I'm sorry I couldn't figure out something so basic and had to ask here, but in the newUser callback function, how do I get a reference to that input element?
{{input action="newUser"}}
I tried param=this this.$() this.get('element') Nothing worked in Ember 1.7
You could try
this.$('input')
which will return a jQuery-style element set on which you can do more jQuery-type things, or
this.get('element').querySelector('input')
this.get('element') will return the view element, so you need to poke down into it to find the input element, whether by tagname as above, or via some other selection mechanism such as id or class.
However, this assumes the action is defined within the view, where this.$ and this.get('element') are defined. It will not work if the action is defined on the controller or route. It is a common Ember pattern to have an action handler on the view, which does view-related things, and then sends some action along to the controller for it to do controller-related things.
However, if you are trying to retrieve the input element just in order to muck with its value, then you can do this much more easily by simply modifying the property bound to the input elements' value.
You don't even need a reference to the element to clear it. Just use data-binding:
http://emberjs.jsbin.com/telat/1/edit
I am facing issue with class name bindings. Here is the jsfiddle code for the same. Logging the number of times binding is called. It is never called when the property is changed.
You appear to have a couple of issues here. Primarily, if you want properties to be recalculated when the contents of an array change, you cannot just depend on the array property itself - it will only fire a change when it is set to a different array. If you depend on myArray.#each instead, your property will be recalculated when the contents change as well.
Next, your template containing the span isn't rendering because you're providing an empty view template in your handlebars view declaration. Change your "HTML" to:
{{view App.contact}}
and your span will appear.
Finally, running Ember.run.sync() does not appear to be enough here. I am not as clear on the reason behind this but...computed properties only update when read (versus observers that update immediately). I would hypothesize that since your computed property is only used by the view and the view may only update on a subsequent run through the JS event loop, your computed property is recalculated only once for all your changes to "subordinates". Change your code to use timeouts and it'll work fine.
Here's a jsfiddle with all of my proposed changes.