Build dist/prism.js as IIFE for synchronous globalThis.Prism

scripts/build.js

@@ -250,7 +250,7 @@
 	renderChunk (code) {
 		const str = new MagicString(code);
 		str.replace(
 			/\/((?:[^\n\r[\\\/]|\\.|\[(?:[^\n\r\\\]]|\\.)*\])+)\/\s*\.\s*source\b/g,
 			(m, /** @type {string} */ source) => {
 				// escape backslashes
 				source = source.replace(
@@ -297,7 +297,7 @@
 	renderChunk (code) {
 		const str = new MagicString(code);
 		str.replace(
 			/^(?<indent>[ \t]+)grammar: (\{[\s\S]*?^\k<indent>\})/m,
 			(m, _, /** @type {string} */ grammar) => `\tgrammar: () => (${grammar})`
 		);
 		return toRenderedChunk(str);
@@ -334,7 +334,8 @@
 	};
 }
 
-const terserPlugin = rollupTerser({
+/** @type {import('@rollup/plugin-terser').Options} */
+const terserOptions = {
 	ecma: 2020,
 	module: true,
 	compress: {
@@ -348,7 +349,8 @@
 		comments: false,
 	},
 	keep_classnames: true,
-});
+};
+const terserPlugin = rollupTerser(terserOptions);
 
 async function clean () {
 	const outputDir = path.join(__dirname, '../dist');
@@ -404,7 +406,6 @@
 	const input = {
 		'index': path.join(SRC_DIR, 'index.js'),
 		'global': path.join(SRC_DIR, 'global.js'),
-		'prism': path.join(SRC_DIR, 'prism.global.js'),
 		'shared': path.join(SRC_DIR, 'shared.js'),
 	};
 	for (const id of languageIds) {
@@ -446,6 +447,24 @@
 				format: 'cjs',
 			},
 		},
+		iife: {
+			rollupOptions: {
+				...defaultRollupOptions,
+				input: path.join(SRC_DIR, 'auto-start.js'),
+				plugins: [
+					...defaultRollupOptions.plugins.slice(0, -1), // remove default terser plugin
+					rollupTerser({ ...terserOptions, module: false }),
+				],
+			},
+			outputOptions: {
+				...defaultOutputOptions,
+				dir: undefined,
+				file: path.join(DIST_DIR, 'prism.js'),
+				format: 'iife',
+				name: 'Prism',
+				exports: 'default',
+			},
+		},
 	};
 
 	try {

src/global.js

@@ -5,5 +5,8 @@ import globalPrism from './core/prism.js';
  *
  * This instance of Prism is unique. Even if this module is imported from
  * different sources, the same Prism instance will be returned.
+ *
+ * When a global build (IIFE) has already set `globalThis.Prism`, this
+ * module reuses that instance so ESM plugins share the same singleton.
  */
-export default globalPrism;
+export default globalThis.Prism?.constructor?.name === 'Prism' ? globalThis.Prism : globalPrism;