如何将#if类型车把助手从ember 1.7转换为ember-cli（2.3）

Question

I have this registered handlebars helper in ember1.7 right now.

var get = Ember.Handlebars.get;
Ember.Handlebars.registerHelper('ifCond', function(val1, val2, options) {
    var context = (options.fn.contexts && options.fn.contexts[0]) || this;
    var val1 = get(context, val1, options.fn);
    if (val1 == val2) {
        return options.fn(this);
    } else {
        return options.inverse(this);
    }
});

The idea is pretty simple: take first parameter as a context property, second parameter as an actual value, and return a boolean based on their equality. So, for example, if I have a property age on an object user,

{{#ifCond user.age "22" }}
  <h2> Twin Twos!</h2>
{{/ifCond}}

would be a snippet I would use to render the h2 element when the condition is fulfilled.

However, I cannot figure out how to translate such a helper for ember-cli.

I've considered making a component, but I need a conditional, not something that renders a specific set of DOM elements. I feel like I'm missing something. How would I be able to make {{#ifCond}} work in Ember 2.3?

EDIT: I found a helper creation doc that let me to this implementation:

import Ember from 'ember';

export function ifCond(params/*, hash*/) {
    return (params[0] === params[1]);
  // return params;
}

export default Ember.Helper.helper(ifCond);

however, for this to work, I would have to write (in the template)

{{#if (ifCond 1 1)}}
  yep
{{/if}}

Is there still a way to actually use the handlebar helper as we could in ember 1.7 ?

Answer 1

After digging around for a good while, it seems that the question edit is the best way forward. It is the accepted way of handlebar helpers from here on out, it seems.

To create a helper, emulate:

import Ember from 'ember';

export function ifCond(params/*, hash*/) {
    return (params[0] === params[1]);
  // return params;
}

export default Ember.Helper.helper(ifCond);

Then, include it in the template in this format.

{{#if (ifCond 1 1)}}
  yep
{{/if}}

This link pointed me towards the right direction: https://guides.emberjs.com/v2.3.0/templates/writing-helpers/

And this one showed me exactly what could be done: http://emberigniter.com/how-to-equals-conditional-comparison-handlebars/

Answer 2

First of all there are no more block helpers :

Legacy Handlebars helpers are removed in favor of the Ember.Helper API. This API does not provide a mechanism for helpers to take a block, but does introduce support for nested helpers which can be used in concert with built-in helpers (like {{#if}} and {{#each}}) to achieve the same ends.

It is recommended to use the helpers just as you did in your example ( {{#if (ifCond 1 1)}} ). If you would decide to go this route I would recommend using the ember-truth-helpers addon. Using it you can throw out your own helper and use it like this:

{{#if (eq user.age "22") }}
  <h2> Twin Twos!</h2>
{{/if}}

I find the truth helpers very flexible and easy to understand and would recommend using them.

Alternatively if you want to simulate your old helper you need to use a component for that, I've made a twiddle to illustrate how you could do it.