not

Unlike the and and or operators, the not operator always returns a boolean value.

{{ not true }} → false
{{ not false }} → true

{{ not 1 }} → false
{{ not 0 }} → true

{{ not "x" }} → false
{{ not "" }} → true

Use the not operator, twice in succession, to cast any value to a boolean value. For example:

{{ 42 | not | not }} → true
{{ "" | not | not }} → false

See Go’s text/template documentation for more information.