Directives
ng-app - attach the Application Module to the page
<html ng-app="store">
ng-controller - attach a Controller function to the page
<body ng-controller="StoreController as store">
ng-show/ng-hide - display a section based on an Express
<h1 ng-show="name"> Hello, {{name}}! </h1>
ng-repeat - repeat a section for each item in an Array
<li ng-repeat="product in store.products"> {{ product.name }}</li>
ng-init - allows us to evaluate an expression in the current scope
ng-class - accepts a key (name of the class to set) and a value, which is the expression to evaluate.
ng-class="{ active:tab === 1}"
ng-model - binds the form element value to the property
ng-submit - allows us to call a function when the form is submitted
Expressions define a 2-way Data Binding, meaning Expressions are re-evaluated when a property changes.