How to broadcast an event down to an element from rootScope in Polymer?

问题

For example, we have root scope

<template is="dom-bind" id="app">
    <div id="element-on-branch"></div>
    <my-element></my-element>
</template>

Then fires an event

this.fire('custom')

It goes to root and then I need to route this event to . How can I broadcast an event or notify branched elements? Thank you!

回答1:

You can use iron-signals.

Fire an iron signal event inside your element:

this.fire('iron-signal', {name: 'mysignal', data: "data"});

Then listen to that signal from anywhere in your webapp using an iron-signals element.

...
<iron-signals on-iron-signal-mysignal="_handleEvent"></iron-signals>

来源：https://stackoverflow.com/questions/32586950/how-to-broadcast-an-event-down-to-an-element-from-rootscope-in-polymer