Atoms are not automatically converted to strings in heex templates

tl;dr

If you’ve got a heex template where you want to insert some data attribute like true, make sure that you convert it to a string first. Otherwise a blank string "" is inserted.

E.g. if you’ve got something like this:

<div class="foobar"
    { if assigns[:multi_select] != nil, do: [{"data-multi-select", Map.get(assigns, :multi_select, true)}] }>

where the assigns[:multi_select] value is true, you must explicitly cast the value to a string:

<div class="foobar"
    { if assigns[:multi_select] != nil, do: [{"data-multi-select", to_string(Map.get(assigns, :multi_select, true))}] }>