Handlebars conditional checked property from Jade template

I'd like my handlebars template that's served to the client to look like

<input type='checkbox' checked={{isChecked}}>

or

<input type='checkbox' {{#if isChecked}}checked{{/if}}>

How can I write a Jade template that will compile to this? from their docs, the checked property will be included if the assigned value is truthy but not actually include the value:

input(type="checkbox", checked="{{isChecked}}")

compiles to

<input type='checkbox' checked>

I've also tried:

input(type="checkbox", checked={{isChecked}})

and

input(type="checkbox", {{#if isChecked}}checked{{/if}})

that just fails to compile, which I understand