Svelte’s templating language is great, in that it looks like HTML. However, for highly dynamic content I need to be able to use the full power of JavaScript, not just #if and #each. For example, given a tree data structure, I want to generate hierarchical table headings. (Demo) In React most apps use JSX templates, but you can drop down to createElement if you need to. Is there a similar path for Svelte? Am I missing something obvious?
If you need access to the DOM node, you can:
Add bind:this={node} to get access to the DOM node:
<script>
import {onMount} from 'svelte'
let node
onMount(() => {
const dynamic = document.createElement('a')
dynamic.innerHTML = "Click me!"
node.appendChild(dynamic)
})
</script>
<div bind:this={node}/>
Add a use directive, this will also get you access to the raw DOM node
<script>
function ninja(node) {
node.innerHTML = "Kawabunga!"
}
</script>
<div use:ninja/>
I would look at the <svelte:self> element, which allows you to create elements that call themselves recursively.
https://svelte.dev/tutorial/svelte-self
Related
I use the Universal style for my QtQuick app and I want to provide a ColorDialog for adjusting the accent color.
I have something like this:
ColorDialog {
id: accChooser
title: "Please choose a color"
onAccepted: {
setGlobalAccentColor(accChooser.color)
}
}
*Note that I cannot simply write Universal.accent=... inside a child item because it has no effect on the parent.See this.
and this function:
function setGlobalAccentColor(accentColor){
Universal.accent = accentColor
}
It works when the function setGlobalAccentColor is defined within the same QML file as accChooser,but if I define that function inside an external JS file (say helpers.js) and import it via:
import "helpers.js" as JSHelpers
and use it this way:
ColorDialog{
...
JSHelpers.setGlobalAccentColor(colorDialog.color)
...
}
it doesn't work.There's no specific error or warning message in the output of the app.
Thanks.
May be it is required to import the universal style in the javascript file.
The documentation universal style says below (look in dependency section)
The Universal style must be separately imported to gain access to the
attributes that are specific to the Universal style
You can try importing as said below into your javascript (helpers.js) file.
.import QtQuick.Controls.Universal 2.12 as JsUniversal
And then try accessing (like example: JsUniversal.accent..).
Note that I cannot simply write Universal.accent=... inside a child item because it has no effect on the parent.See this.
While setting it to the child won't affect your whole application, you can set it directly to the whole window.
Window.window.Universal.accent = accentColor;
Universal is an attached object, you can attach it to an abitrary object, not just the current one, by doing <object>.<AttachingType>.
We attach it to the parent window by accessing the window via another attached property: Window.window.
How can I add HTML objects to an event?I would like to do something like this:
Template.Schedule.events({
'dblclick .mycol' (event){
event.target.childNodes.append("<strong>Test</strong>");
}
});
I know I could style it and change the innerHTML and so on for the given example, but I actually want to add other HTML objects, like a select-tag, how can I do that?
The vanilla JS way
You could use innerHTML here to change the html content of the clicked element:
'dblclick .mycol' (event){
const target = event.currentTarget
target.innerHTML = target.innerHTML + "<strong>Test</strong>"
}
If you want to manipulate the parent in the event you can use outerHTML
The jQuery way
Your approach of using append is requiring jQuery:
'dblclick .mycol' (event){
$(event.currentTarget).append($("<strong>Test</strong>"))
}
Bonus: Optimization for using jQuery
In a meteor blaze template-events each event has a reference to the template instance. This template instance keeps a reference to a jQuery object and it's part of the DOM that it manipulates.
template.$ returns a jQuery object of those same elements. jQuery
objects are similar to arrays, with additional methods defined by the
jQuery library.
The template instance serves as the document root for the selector.
Only elements inside the template and its sub-templates can match
parts of the selector.
You can access it via templateInstance.$ if your seconds event parameter is namend templateInstance. With
'dblclick .mycol' (event, templateInstance){
templateInstance.$(event.currentTarget).append($("<strong>Test</strong>"))
}
This saves jQuery the need to traverse the whole DOM, makes it more efficient on large documents.
The Meteor Blaze way
Now these are neat little tricks when there is need for manipulation on a small scale. However, you may want your app to be scalable and profit all the time from the Blaze rendering engine.
In such cases you may rather want to generate a way of dynamically inserting templates.
Consider the following template, that is nowhere imported yet:
rowcontent.html
<template name="rowcontent">
<strong>Test</strong>
<p>someData{{someData}}</p>
</template>
rowcontent.js
import './rowcontent.html' // currently just the import
You can dynamically add it at runtime to an element using Blaze.renderWithData so:
'dblclick .mycol' (event, templateInstance) {
import './rowcontent.js' // use the right path here
Blaze.renderWithData(Template.rowcontent, {someData: 'toBePassedToRowContent'}, event.currentTarget)
}
which will result in:
This is my col Test
someDatatoBePassedToRowContent
The advantage of this approach is that you can pass the data to the template and have all the reactive benefits remaining, thus handle the newly added template like any other template in Meteor.
Alternatives
Declarative dynamic templates using Template.dynamic
I need to make the Selector Tag of my app.component.html using a variable.
Suppose variable name is: componentVar:string
I need my app.component.html:
<componentVar></componentVar> or <app-componentVar></app-componentVar>
You can dynamically create your components within a ViewcontainerRef like this:
https://stackblitz.com/edit/angular-4asbmc
(Don't forget to add the components you want to dynamically inject in your dom in your app module's entryComponents)
Once you are able to insert the components you shoud be able to manage which components have to be inserted into your with conditions.
Edit
You can iterate on an array of component that could look like this:
let componentArray = [HeaderComponent, BannerComponent, FooterComponent];
and then iterate over this array calling the method that inserts your components in your viewcontainer reference.
createComponent(component) {
const factory = this.factoryResolver.resolveComponentFactory(component);
const componentRef = factory.create(yourViewContainerRef.parentInjector);
yourViewContainerRef.insert(componentRef.hostView);
}
Though it would be musch easier to just call your components from your app component html template, and have something like this in your template:
<app-header *ngIf="yourConditions..."></app-header>
<app-banner *ngIf="otherConditions..."></app-banner>
<!-- and so on.... -->
In dart we can obtain dom element through 'querySelector' method. But I need a reverse kind method: insert data into "dart component" element from Javascript. Is there a way to achieve that?
I have try:
html file:
<comp></comp>
<script>
document.getElementById('mydiv').text = "HELLO";
document.getElementById('myd').text = "HELLO";
</script>
dart component:
#Component (
selector: 'comp',
template: '<div #mydiv id="myd">12345</div>',
)
class ModelerComponent {
PS: I need that because my js library requires element id, and there is no option to port it.
Thanks to comments, I've solve the problem:
I place code which initializes JS library into ngOnInit() method of a component. So the js library is initialised right after an angular component.
Im not really sure if Im understanding correctly the way observables work and how to get references from mounted tags. I have a component. Within this component we have a component and a component. The purpose is to avoid coupling between components. Because of that, I would like that my search component triggers an event when a search is done(a button is clicked). This event should be caught by the component which will filter the collection data based on the search.
The index.html file load the tag by using:
index.html
riot.mount(".content", "page", null);
The page is defined as follow:
page.js
<page>
<!-- Search tag controls -->
<search id="searchTag"></search>
<!-- Collection data to display -->
<collection id="collectionTag"></collection>
</page>
The component script is briefly defined like:
search.js
var self = this;
riot.observable(self);
<!-- This function is called when the user click on the button. -->
self.filtering = function()
{
<!-- We get data from inputs -->
var info = Getting data from inputs;
<!-- Trigger the event hoping that someone will observe it -->
self.trigger("filterEvent", info);
}
How can I make the component observe for that event?
To me it seems that I should be able to get references from search tag and collection tag in the page.js. By doing so I could connect the events like follow:
searchComponent = riot.mount('search');
collectionComponent = riot.mount('collection');
searchComponent.on('filterEvent', function()
{
<!-- Trigger function to filter collection data -->
collectionComponent.trigger('filterData');
});
Right now I cannot make it work like that.
At the point of execution, searchComponent and collectionComponent are not defined.
I tried also getting references of these component by using this.searchTag and this.collectionTag instead of mounting them but at the time the code is executed, the components have not been mounted and so I dont get a reference to them.
Any ideas to make it work?
Inspired by the answer given by #gius, this is now my preferred method for sending events in RiotJS from one tag to another.. and it is great to work with!
The difference from #gius approach being that, if you use a lot of nested tags, passing a shared Observable to each tag falls short, because you would need to pass it again and again to each child tag (or call up from the child tags with messy this.parent calls).
Defining a simple Mixin, like this (below), that simply defines an Observable, means that you can now share that in any tag you want.
var SharedMixin = {
observable: riot.observable()
};
Add this line to your tags..
this.mixin(SharedMixin);
And now, any tag that contains the above line can fire events like..
this.observable.trigger('event_of_mine');
..or receive events like this..
this.observable.on('event_of_mine',doSomeStuff());
See my working jsfiddle here http://jsfiddle.net/3b32yqb1/5/ .
Try to pass a shared observable to both tags.
var sharedObservable = riot.observable();
riot.mount('search', {observable: sharedObservable}); // the second argument will be used as opts
riot.mount('collection', {observable: sharedObservable});
And then in the tags, just use it:
this.opts.observable.trigger('myEvent');
this.opts.observable.on('myEvent', function() { ... });
EDIT:
Or even better, since your search and collection tags are child tags of another riot tag (page) (and thus you also don't need to mount them manually), you can use the parent as the shared observable. So just trigger or handle events in your child tags like this:
this.parent.trigger('myEvent');
this.parent.on('myEvent', function() { ... });
Firstly I do not understand your file structure !
In your place I would change filenames :
page.js --> page.tag
search.js --> search.tag
And i dont see your search tag in search.js code.
So I dont see your Collection tag file ...
Are you sure that this one use this code ?
riot.observable({self|this});
Because it's him who will receive an Event.
For me when I use Riot.js(2.2.2) in my browser, if I use
searchComponent = riot.mount('search');
searchComponent will be undefined
But with this code you can save your monted tag reference :
var searchComponent ={};
riot.compile(function() {
searchComponent = riot.mount('search')[0];
});
Another option is to use global observables, which is probably not always best practice. We use Riot's built in conditionals to mount tags when certain conditions are met rather than directly mounting them via JS. This means tags are independent of each other.
For example, a single observable could be used to manage all communication. This isn't a useful example on its own, it's just to demonstrate a technique.
For example, in a plain JS file such as main.js:
var myApp = riot.observable();
One tag file may trigger an update.
var self = this;
message = self.message;
myApp.trigger('NewMessage', message);
Any number of other tag files can listen for an update:
myApp.on('NewMessage', function(message) {
// Do something with the new message "message"
console.log('Message received: ' + message);
});
Maybe overkill but simple. let riot self observable
riot.observable(riot);
So you can use
riot.on('someEvent', () => {
// doing something
});
in a tag, and
riot.trigger('someEvent');
in another.
It's not good to use global variable, but use an already exists one maybe acceptable.