grunt-requirejs - how to optimize CSS? - css

Question

I'm using Yeoman, and are trying to setup requirejs to optimise my CSS files.
I have this in my Gruntfile.js:
requirejs: {
css: {
options: {
optimizeCss: 'standard',
cssIn: 'app/styles/main.css',
out: 'app/styles/main.min.css'
}
}
}
When I run the build command I get an error:
grunt build
Running "requirejs:css" (requirejs) task
>> Error: TypeError: new path must be a string
>> at Object.fs.renameSync (fs.js:439:18)
Warning: Task "requirejs:css" failed
I'm not really sure what's happening there, or how to debug that.
Does anyone know what the problem could be?

Answer 1

Never mind, I worked it out.
The silly useminPrepare task that ships with Yeoman stuffs around with the grunt-requirejs configuration. Kind of annoying, esp. since the point of me wanting to use grunt-requirejs was because I didn't like how usemin worked to begin with.
UPDATE:
This is my configuration that works:
//index.html:
<!-- build:js scripts/scripts.js -->
<script data-main="scripts/main" src="components/requirejs/require.js"></script>
<!-- endbuild -->
//Gruntfile.js:
requirejs: {
js: {
options: {
baseUrl: '<%= yeoman.tmp %>/scripts',
out: '<%= yeoman.dist %>/scripts/scripts.js',
name: 'main',
optimize: 'none',
mainConfigFile: '<%= yeoman.app %>/scripts/main.js',
useStrict: true,
wrap: true
}
},
css: {
options: {
optimizeCss: 'standard',
cssIn: '<%= yeoman.app %>/styles/main.css',
out: '<%= yeoman.dist %>/styles/main.css'
}
}
},
useminPrepare: {
html: '<%= yeoman.app %>/index.html',
options: {
dest: '<%= yeoman.dist %>'
}
},
usemin: {
html: '<%= yeoman.dist %>/index.html',
options: {
dirs: ['<%= yeoman.dist %>']
}
}
grunt.registerTask('build', [
'requirejs:js',
'requirejs:css',
'useminPrepare', //must be after requirejs:css as it breaks its config params
'usemin'
]);
NOTE: There is still an underlying bug in grunt-usemin where it (incorrectly) tries to alter the requirejs config for the requirejs:css configuration. I've reported that here