Length check in a handlebars.js {{#if}} conditional

Question

Is there a way in handlebars to check the length of a value? Something like this:

{{#if value.length > 20}
...do something
{{else}}
...do something else
{{/if}}

Answer 1

It's not clear what your value is, a string or an array?

If it's an array, you don't need a helper! You can check if the item at length exists:

{{#if items.[20]}}

Here's a working example to display different messages if the user has one item, vs. multiple items:

{{#if items.[1]}}
You have the following items:
{{#each items}}
* {{this}}
{{/each}}
{{else}}
You have one item: {{items.[0]}}
{{/if}}

Try it at http://tryhandlebarsjs.com/ with sample data like

{
  items: ["foo", "bar"]
}

Not needing a helper is very important for using Handlebars in dynamic templates for mail delivery services (Sparkpost, Sendgrid, Mandrill etc.), which don't allow defining helpers (though Sparkpost has a much richer syntax than Sendgrid).

Answer 2

Create Handlebars helper like below:-

Handlebars.registerHelper('checklength', function (v1, v2, options) {
'use strict';
   if (v1.length>v2) {
     return options.fn(this);
  }
  return options.inverse(this);
});

and use this like:-

      {{#checklength jobTitle 20}}   //jobtitle is property and 20 is length
             <p>Up to 20</p>
      {{else}}
             <p>Less then 20</p>
      {{/checklength}}

Demo