Remove symlink. GH pages can't build with it.

docs/dist

@@ -1 +0,0 @@
-../dist

gulp/tasks/copy-dist.js

@@ -0,0 +1,7 @@
+const gulp = require('gulp');
+
+// Copy dist directory to docs. GitHub pages don't work with symlinks.
+module.exports = function copyDist() {
+  return gulp.src('dist/*')
+    .pipe(gulp.dest('docs/dist/'));
+};

gulp/tasks/set-watching.js

@@ -2,17 +2,14 @@ const gulp = require('gulp');
 const config = require('../config');
 const cssTask = require('./css');
 const testTask = require('./test');
-const scriptsTask = require('./scripts');
 
 module.exports = function setWatching(done) {
   config.watch = true;
   gulp.watch('docs/_scss/**/*.scss', cssTask);
   gulp.watch('test/*', testTask);
 
-  // Since Jekyll doesn't watch sym-linked directories, copy the files manually.
-  gulp.watch('src/*', () => scriptsTask().then(
-    () => gulp.src('dist/*').pipe(gulp.dest('docs/_site/dist/')) // eslint-disable-line
-  ));
+  // Copy dist directory to docs. GitHub pages don't work with symlinks.
+  gulp.watch('src/*', gulp.series('scripts', 'copy-dist'));
 
   done();
 };

gulpfile.js

@@ -1,6 +1,7 @@
 const gulp = require('gulp');
 
 gulp.task('scripts', require('./gulp/tasks/scripts'));
+gulp.task('copy-dist', require('./gulp/tasks/copy-dist'));
 gulp.task('set-watching', require('./gulp/tasks/set-watching'));
 gulp.task('css', require('./gulp/tasks/css'));
 gulp.task('jekyll', require('./gulp/tasks/jekyll'));
@@ -9,7 +10,8 @@ gulp.task('test', require('./gulp/tasks/test'));
 gulp.task('watch', gulp.series(
   'set-watching',
   gulp.parallel('css', 'scripts'),
+  'copy-dist',
   'jekyll'
 ));
 
-gulp.task('default', gulp.series('scripts', 'test'));
+gulp.task('default', gulp.series('scripts', 'test', 'copy-dist'));