chore(sass): abstract sass-importer from compiler-sass script (#456)

scripts/compile-sass.js

@@ -2,23 +2,17 @@
 
 var gulp = require('gulp-help')(require('gulp'));
 var sass = require('gulp-sass');
-var path = require("path");
 var sourcemaps = require('gulp-sourcemaps');
 var config = require('../build.conf');
+var sassImporter = require('./sass-importer');
 
 gulp.task('compile-sass', 'Build the module styles', function() {
   return gulp
     .src(config.paths.styles)
     //.pipe(sourcemaps.init()) // add later on when not using relative routes for node_modules scss
     .pipe(sass({
       errLogToConsole: true,
-      importer: function(url, prev, done) {
-        if (url.indexOf('~') === 0) {
-          url = 'node_modules/' + url.substring(1, url.length);
-          return {file: path.relative(path.dirname(prev), url)};
-        }
-        return {file: url};
-      }
+      importer: sassImporter,
     }))
     .pipe(sourcemaps.write('.'))
     .pipe(gulp.dest('deploy/'));

scripts/sass-importer.js

@@ -0,0 +1,9 @@
+var path = require("path");
+
+module.exports = function sassImporter(url, prev, done) {
+  if (url.indexOf('~') === 0) {
+    url = 'node_modules/' + url.substring(1, url.length);
+    return {file: path.relative(path.dirname(prev), url)};
+  }
+  return {file: url};
+}