Merge branch 'dev'

# Conflicts:
#	package-lock.json
#	package.json

Gulpfile.js

@@ -0,0 +1,66 @@
+const fs = require('fs');
+const gulp = require('gulp');
+const clean = require('gulp-clean');
+const insert = require('gulp-insert');
+const uglify = require('gulp-uglify-es').default;
+const concat = require('gulp-concat');
+const mergeStream = require('merge-stream');
+const rollup = require('gulp-rollup');
+const rollupResolve = require('rollup-plugin-node-resolve');
+const PolymerProject = require('polymer-build').PolymerProject;
+
+
+const WEB_COMPONENTS_POLYFILL = require.resolve('@webcomponents/webcomponentsjs/webcomponents-bundle.js');
+const WEB_COMPONENTS_ES5_ADAPTER = require.resolve('@webcomponents/webcomponentsjs/custom-elements-es5-adapter.js');
+const IE_POLYFILLS = [
+    require.resolve('url-polyfill/url-polyfill.min.js'),
+    require.resolve('babel-polyfill/dist/polyfill.min.js'),
+];
+
+const bundle = (options) => {
+    // Bundle main sources and dependencies
+    const project = new PolymerProject(JSON.parse(fs.readFileSync('./polymer.json', 'utf8')));
+    const version = JSON.parse(fs.readFileSync('./package.json', 'utf8')).version;
+    let bundleStream = mergeStream(project.sources(), project.dependencies());
+
+    bundleStream = bundleStream
+        .pipe(uglify())
+        .pipe(rollup({
+            allowRealFiles: true,
+            input: 'mammooc-rating-widget.js',
+            output: {
+                format: 'iife',
+            },
+            plugins: [
+                rollupResolve({
+                    module: false,
+                    jsnext: true,
+                }),
+            ],
+        }))
+        .pipe(insert.prepend(`/* mammooc-rating-widget v${version} */\r\n`));
+
+    // Copy polyfills to output
+    let polyfillsStream = gulp.src(WEB_COMPONENTS_POLYFILL);
+    if(options.compile) {
+        polyfillsStream = mergeStream(
+            polyfillsStream,
+            gulp.src(WEB_COMPONENTS_ES5_ADAPTER),
+            gulp.src(IE_POLYFILLS).pipe(concat('polyfills-ie.js'))
+        );
+    }
+
+    return mergeStream(bundleStream, polyfillsStream)
+        .pipe(gulp.dest(options.dest));
+};
+
+const cleanDir = (dir) => gulp.src(dir, {read: false, allowEmpty: true}).pipe(clean());
+gulp.task('clean-es5', () => cleanDir('build/es5'));
+gulp.task('clean-es6', () => cleanDir('build/es6'));
+gulp.task('clean', gulp.parallel('clean-es5', 'clean-es6'));
+
+gulp.task('bundle-es5', () => bundle({compile: true, dest: 'build/es5'}));
+gulp.task('bundle-es6', () => bundle({compile: false, dest: 'build/es6'}));
+gulp.task('bundle', gulp.series('clean', gulp.parallel('bundle-es5', 'bundle-es6')));
+
+gulp.task('default', gulp.series('bundle'));