handlebars.jsmailgun

Mailgun's Handlebar implementation: string comparison in "if" without extra helpers

Using Mailgun's Handlebars implementation I'd like to have multi-language templates. I.e. wrap each text block in a condition and display the language passed as parameter.

Now for the crucial part: If the language parameter is missing or has a value not supported (i.e. no specified in the template) then an English string should be displayed as fallback language.

If Mailgun were to support custom helpers you could define a helper according to this SO answer like Handlebars.registerHelper('eq', (a, b) => a == b)

And then do:

{{#if (eq language "sv")}}Hej
{{else if (eq language "de")}}Hallo
{{else}}Hello
{{/if}}

However, as far as I know, there is no way to define own helpers in Mailgun.

So, how would I do this without extra helpers?

I know that I could, theoretically, transform the input to booleans and then do something like

{{#if isSwedish}}Hej
{{else if isGerman}}Hallo
{{else}}Hello
{{/if}}

But that would be very inconvenient for me and I would rather prefer to pass a string property language.

The Mailgun support told me that it must be somehow possible in Handlebars but refused to tell me how exactly.

Solution

  • The Mailgun API docs mentions an equal block helper which looks to behave just like the eq helper you suggested in your post. Therefore, I would assume the following template would achieve your objective:

    {{~#equal language "sv"~}}
  Hej
{{~else equal language "de"~}}
  Hallo
{{~else~}}
  Hello
{{~/equal~}}

    Note: I am using ~ characters to eliminate extra whitespace caused by the indentations in the template for readability. See: https://stackoverflow.com/a/23636497/3397771