Use rollup so we don't need to rely on sprockets

.gitignore

@@ -4,6 +4,7 @@
 .config
 .yardoc
 Gemfile.lock
+package-lock.json
 InstalledFiles
 _yardoc
 coverage
@@ -17,4 +18,5 @@ test/version_tmp
 tmp
 jetty
 spec/internal
-.internal_test_app
+.internal_test_app
+node_modules

app/javascript/blacklight_gallery/index.js

@@ -0,0 +1,5 @@
+import 'imagesloaded.min'
+import 'masonry.min'
+
+import './slideshow'
+import './masonry'

lib/generators/blacklight_gallery/templates/blacklight_gallery.js

@@ -1,2 +1,4 @@
-//= require blacklight_gallery/default
-//= require blacklight_gallery/osd_viewer
+import 'blacklight_gallery'
+import OpenSeadragon from 'openseadragon'
+window.OpenSeadragon = OpenSeadragon
+import 'openseadragon-rails'

package.json

@@ -2,7 +2,11 @@
   "name": "blacklight-gallery",
   "version": "4.6.4",
   "description": "Gallery views for Blacklight search results",
-  "main": "app/assets/javascripts/blacklight_gallery/default.js",
+  "main": "app/assets/javascripts/blacklight_gallery/blacklight-gallery.esm.js",
+  "type": "module",
+  "scripts": {
+    "prepare": "rollup --config rollup.config.js --sourcemap && ESM=true rollup --config rollup.config.js --sourcemap"
+  },
   "files": [
     "app/assets/javascripts/blacklight_gallery/*.js",
     "vendor/assets/javascripts/*.js",
@@ -18,9 +22,13 @@
     "url": "https://github.com/projectblacklight/blacklight-gallery/issues"
   },
   "homepage": "https://github.com/projectblacklight/blacklight-gallery#readme",
-  "devDependencies": { },
+  "devDependencies": {
+    "rollup": "^4.24.0",
+    "rollup-plugin-includepaths": "^0.2.4"
+  },
   "dependencies": {
     "blacklight-frontend": ">=7.1.0 <9",
+    "openseadragon-rails": "1.0.0",
     "jquery": ">=3.0"
   }
 }

rollup.config.js

@@ -0,0 +1,31 @@
+import includePaths from 'rollup-plugin-includepaths';
+
+
+const BUNDLE = process.env.BUNDLE === 'true'
+const ESM = process.env.ESM === 'true'
+
+const fileDest = `blacklight-gallery${ESM ? '.esm' : ''}`
+const external = []
+const globals = {}
+
+let includePathOptions = {
+  include: {},
+  paths: ['app/javascript', 'vendor/assets/javascripts'],
+  external: [],
+  extensions: ['.js']
+};
+
+const rollupConfig = {
+  input: 'app/javascript/blacklight_gallery/index.js',
+  output: {
+    file: `app/assets/javascripts/blacklight_gallery/${fileDest}.js`,
+    format: ESM ? 'es' : 'umd',
+    globals,
+    generatedCode: { preset: 'es2015' },
+    name: ESM ? undefined : 'BlacklightGallery'
+  },
+  external,
+  plugins: [includePaths(includePathOptions)]
+}
+
+export default rollupConfig