Accessibility Labels

components.a11y-label.js

import Ember from 'ember';

const {
  Component,
  computed,
  get,
  guidFor
} = Ember;

export default Component.extend({
  tagName: '',
  computed,
  
  targetId: computed(function() {
    return guidFor(this);
  }),
  
  actions: {
    register(child) {
      this.set('targetId', get(child, 'id'));
    }
  }
});

components.my-input.js

import Ember from 'ember';

const {
  Component,
  run
} = Ember;

export default Component.extend({
  tagName: 'input',
  register: null,
  
  didInsertElement() {
    run.next(() => {
      this.sendAction('register', this);
    });
  }
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

templates.application.hbs

<h1>Setting Accessibility Id</h1>
<br>
<h3>Scenario 1: target is an element with a known ID</h3>
{{#a11y-label targetId="foo"}}
  <input id="foo">
{{/a11y-label}}

<h3>Scenario 2: target is an element with an unknown ID</h3>
<p>Note: for this to be true, the id would need to be programmatically generated by something else deeper in scope, a situation we should be avoiding anyway.  The implementation details here are the same as in scneario 4.</p>

<h3>Scenario 3: target is an element without an ID</h3>
{{#a11y-label as |targetId|}}
  <input id="{{targetId}}">
{{/a11y-label}}

<h3>Scenario 4: target is a component's element</h3>

{{#a11y-label as |_ register|}}
  {{my-input register}}
{{/a11y-label}}

<br>
{{outlet}}
<br>
<br>

templates.components.a11y-label.hbs

<label for="{{targetId}}">{{text}}</label>
{{yield targetId (action "register")}}

twiddle.json

{
  "version": "0.10.5",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "2.8.0",
    "ember-data": "2.8.0",
    "ember-template-compiler": "2.8.0",
    "ember-testing": "2.8.0"
  },
  "addons": {}
}