RiotJS - How to pass events between subtags using

问题:

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?

回答1:

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];
});

回答2:

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() { ... });

回答3:

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/ .

回答4:

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);
});

回答5:

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.