limited-items

components.limited-items\.js

import Component from '@glimmer/component';

export default class extends Component {
  get shouldLimit() {
    return this.args.items.length > this.args.showMax;
  }
  
  get items() {
    if (this.shouldLimit) {
      const [...items] = this.args.items;
      return items.splice(0, items.length - (this.args.showMax - 1));
    } else {
      return this.args.items; 
    }
  }
  
  get remaining() {
    return this.args.items.length - this.args.showMax;
  }
}

controllers.application\.js

import Controller from '@ember/controller';

export default class ApplicationController extends Controller {
  options = [
    { name: 'A' },
    { name: 'B' },
    { name: 'C' },
    { name: 'D' },
    { name: 'E' },
  ]
}

templates.application\.hbs

<h1>Welcome to {{this.appName}}</h1>
<br>
<LimitedItems @items={{this.options}} @showMax={{3}} as |item|>
	{{item.name}}
</LimitedItems>
<br>
{{outlet}}
<br>
<br>

templates.components.limited-items\.hbs

{{#each this.items as |item|}}
  {{yield item}}
{{/each}}

{{#if this.shouldLimit}}
  <button type="button">+{{this.remaining}}</button>
{{/if}}

twiddle\.json

{
  "version": "0.17.0",
  "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/3.3.1/jquery.js",
    "ember": "3.17.0",
    "ember-template-compiler": "3.17.0",
    "ember-testing": "3.17.0"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}