watch single file and compile if a dependency changes

[zsitro]

Hi, I can't find in the guide how to add a watch task for a single styl file and make it compile when an imported styl file has changed.

For example:

    watch: {
        stylesheets: {
            files: 'source/main.styl',
            tasks: [ 'stylesheets' ]
        },
}

If main.styl has an @import "dependency1" and I change dependency1.styl the main.styl won't be compiled like the regular stylus command-line watcher would do which would watch every changes in imported files..

Can anyone advise on this? Thanks in advance!

[tkellen]

The stylus command line watcher knows how to process the stylus dependency tree because it was built for stylus. Watch is a general use utility--it doesn't know how to trace dependencies for every type of input you might ultimately invoke a task for. You'll need to provide the dependency listing yourself. Thankfully, Grunt has great built-in utilities for handling complex globbing: http://gruntjs.com/configuring-tasks

[tkellen]

Whoops, the link I meant to send was:
http://gruntjs.com/configuring-tasks#globbing-patterns

[zsitro]

Thanks, I managed to do this :)
watch files: 'source/**/*.styl' and bind it to a stylus task with src: [ 'main.styl']