What are Helpers in Handlebar.js? how can you register it?

Helpers are basically regular functions that take the name of the helper with the helper function as arguments. You can register expression Helper by using the following code:

 Handlebars.registerHelper("last", function(array) {
    return array[array.length - 1];
});

After registration, it can be called anywhere in your templates. Handlebars take the expression's return value and write it into the template.