New Twiddle

controllers.application\.js

import Controller from '@ember/controller';
import { tracked } from "@glimmer/tracking";
import { action } from "@ember/object";

export default class ApplicationController extends Controller {
  appName = 'Ember Twiddle';
  @tracked lat = 38.77;
  @tracked long = -100.79;
  @tracked zoom = 3;

	@action
  onMapLoad(event) {
    this.map = event.target;
    this.invalidateSize();
  }

	@action
  onTabChange(event) {
    this.invalidateSize();
  }

  invalidateSize() {
    // ember-bootstrap tabs do not have any event
    // that fires when the tab is finished transitioning
    // so we have to tell leaflet to
    // recalculate its size after X ms, ideally equal to the
    // css transition duration
    setTimeout(() => {
      this.map?.invalidateSize();
    }, 200);
  }
}

styles.app\.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}
.leaflet-container {
  height: 300px;
}

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>
<br>
<br>
{{outlet}}
<BsTab @onChange={{this.onTabChange}} as |tab|>
  <tab.pane @title="Tab 1">
    <LeafletMap class="esri-map" @lat={{this.lat}} @lng={{this.long}} @zoom={{this.zoom}} @onLoad={{this.onMapLoad}} as |layers|>
                        <layers.tile @url="https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png"/>
                    </LeafletMap>
  </tab.pane>
  <tab.pane @title="Tab 2">
    <p>At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Temporibus autem quibusdam et aut officiis debitis aut rerum necessitatibus saepe eveniet ut et voluptates repudiandae sint et molestiae non recusandae. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.</p>
  </tab.pane>
</BsTab>
<br>
<LeafletMap class="esri-map" @lat={{this.lat}} @lng={{this.long}} @zoom={{this.zoom}} as |layers|>
                        <layers.tile @url="https://{s}.basemaps.cartocdn.com/light_all/{z}/{x}/{y}.png"/>
                    </LeafletMap>
<br>
<br>

twiddle\.json

{
  "version": "0.17.1",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.js",
    "ember": "3.18.1",
    "ember-template-compiler": "3.18.1",
    "ember-testing": "3.18.1",
    "leaflet": "1.7.1",
    "bootstrap": "4.5.3"
  },
  "addons": {
    "@glimmer/component": "1.0.0",
    "ember-bootstrap": "3.1.4",
    "ember-leaflet": "4.1.1"
    
  }
}