Use Handlebars in EmberJS

Question

I am trying to use a custom helper in my Ember project. So I have done

bower install --save handlebars

and then under helpers\\compare.js, I have

import Handlebars from 'handlebars';

Handlebars.registerHelper('compare', function (lvalue, rvalue, options) {
}

Is this the correct way to import Handlebars js and use it inside helper ?

Update

I am now getting:

Assertion Failed: Helpers may not be used in the block form, for example {{#my-helper}}{{/my-helper}}. Please use a component, or alternatively use the helper in combination with a built-in Ember helper, for example {{#if (my-helper)}}{{/if}}.

I want to use the following

{{#compare model.someCount 0 operator = ">"}}

Answer 1

UPDATE Here's a JSBin showing how you would use a component to accomplish this instead of a helper, since block helpers aren't really supported in generated helpers:http://emberjs.jsbin.com/puminocuva/edit?html,js,console,output . Keep in mind components need to be named with a - in them, which is why I named it my-compare and not just compare

---

The docs are pretty straightforward on creating helpers: http://guides.emberjs.com/v1.13.0/templates/writing-helpers/

If you're using Ember CLI 1.13.x with Ember 1.13, I'm not sure how that file above was generated. You should use ember g helper compare in your Ember CLI console to create files.

If you find yourself needing to make comparisons in your view, then I would think you'd want your logic to be in the controller and just generate a computed property such as:

// some/controller.js
import Ember from 'ember';

const { computed } = Ember;

export default Ember.Controller.extend({
  // (...)
  countGreaterThanTen: computed('model.count', ()=> {
    return this.get('model.count') > 10;
  }),
  // (...)
});

and use {{#if countGreaterThanTen}} stuff here {{/if}} in your template rather than perform complex logic in there via helpers.

Update Also, your error is because you're trying to use a helper with an opening block (that's what the # is). When using your own helper in a template, you would just use {{compare}} and not {{#compare}} .