With vs. Let

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'With vs. Let'
});

templates.application.hbs

<h3>WITH (truthy)</h3>

{{#with "I am truthy" as |foo|}}
	<div>{{foo}}</div>
{{/with}}

<hr>

<h3>WITH (falsy)</h3>

{{#with null as |foo|}}
	<div>{{foo}}</div>
{{/with}}

<hr>

<h3>LET</h3>

{{#let "I am truthy" null "I am truthy too" as |foo bar baz|}}
	<div>{{foo}}</div>
  <div>{{bar}}</div>
  <div>{{baz}}</div>
{{/let}}

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "2.12.2",
    "ember-let": "0.7.1"
  }
}