User input sass watching.

gulpfile.js

/**
 * HN Build Tools
 * Contains build tools for developing HNReactive themes. This includes SASS compilation,
 * CSS/JS minification and concatenation.
 * @type {*|Gulp}
 */
"use strict";

var gulp       = require('gulp');
var $          = require('gulp-load-plugins')();
var theme      = 'HNReactiveChild';
var parentDir  = '../HNReactive/Library/scss/';
var foundation = '../HNReactive/vendor/foundation/';

var sassPaths = [
    foundation + 'bower_components/foundation-sites/scss',
    foundation + 'bower_components/motion-ui/src'
];

gulp.task('sass', function() {
    $.util.log('Change detected. Building ' + theme + ' CSS...');
    return gulp.src('../' + theme + '/Library/scss/app.scss')
        .pipe($.sass({
            includePaths: sassPaths
        })
        .on('error', $.sass.logError))
        .pipe(gulp.dest('../' + theme + '/Resource/css'));
});

gulp.task('watch-child', ['sass'], function() {
    gulp.src('base.scss')
        .pipe($.prompt.prompt(
            {
                'type': 'input',
                'name': 'theme',
                'message': 'Target theme slug?'
            },
            function(res) {
                if( res.theme && 0 <= res.theme.length ) {
                    theme = res.theme;
                }
                $.util.log(theme);
                gulp.watch([
                    '../' + theme + '/Library/scss/**/*.scss',
                    parentDir + '/hn-reactive/**/*.scss'
                ], ['sass']);
            }));
});