Localize an attribute with l20n

Question

I'd like to localize a placeholder attribute with L20N. I can't find anything in their documentation, and doing this (unsurprisingly) doesn't work.

<input type="text" data-l10n-id="email" />

Answer 1

A normal translation (meaning you want to replace the content) is written like this:

<test "this is a translated text">

You can then translate attributes like this:

<test "this is a translated text" title:"this is the title">

In your case, you only want the attribute, so this will work:

<test placeholder:"this is a translated text">

The HTML should be

<input type="text" data-l10n-id="test" placeholder="" />