In your case, the navigation.jade file lacks either a mixin filter declaration or its connection from an external file.
For example, the structure may be as follows.
src / blocks / navigation / navigation.jade
include ../../mixins/filter .navigation .container .navigation-row +filter
src / mixins / filter.jade
mixin filter div some text
src / pages / index.jade
include ../blocks/navigation/navigation .other-1 .other-2 Example text.
Then, when converting the entire src directory to HTML, everything will be converted, including mixins.
To exclude unnecessary directories from conversion: you need to either think about the structure, or explicitly specify what to convert and / or exclude.
pug srcorpug src/pages? Or something similar. You probably also have blocks in blocks /, but conversion should be done only for src / pages files. That is, something likepug src/pages, notpug src. - Alexander Bragin