Remove the need to provide an output name for IIFE bundles

src/finalisers/iife.ts

@@ -48,9 +48,8 @@ export default function iife(
 	const args = external.map(m => m.name);
 
 	if (hasExports && !name) {
-		error({
-			code: 'INVALID_OPTION',
-			message: `You must supply "output.name" for IIFE bundles.`
+		warn({
+			message: `If you do not supply "output.name", you may not be able to access the exports of an IIFE bundle.`
 		});
 	}
 
@@ -68,9 +67,9 @@ export default function iife(
 
 	let wrapperIntro = `(function${_}(${args.join(`,${_}`)})${_}{${n}${useStrict}`;
 
-	if (hasExports && (!extend || !namedExportsMode)) {
+	if (hasExports && (!extend || !namedExportsMode) && name) {
 		wrapperIntro =
-			(useVariableAssignment ? `${varOrConst} ${name}` : thisProp(name as string)) +
+			(useVariableAssignment ? `${varOrConst} ${name}` : thisProp(name)) +
 			`${_}=${_}${wrapperIntro}`;
 	}
 

test/function/samples/error-missing-umd-name/_config.js

@@ -0,0 +1,8 @@
+module.exports = {
+	description: 'throws an error if no name is provided for a UMD bundle',
+	options: { output: { format: 'umd' } },
+	generateError: {
+		code: 'INVALID_OPTION',
+		message: 'You must supply "output.name" for UMD bundles.'
+	}
+};

test/function/samples/error-missing-umd-name/main.js

@@ -0,0 +1 @@
+export const x = 42;

test/function/samples/warn-missing-iife-name/_config.js

@@ -0,0 +1,10 @@
+module.exports = {
+	description: 'warns if no name is provided for an IIFE bundle',
+	options: { output: { format: 'iife' } },
+	warnings: [
+		{
+			message:
+				'If you do not supply "output.name", you may not be able to access the exports of an IIFE bundle.'
+		}
+	]
+};

test/function/samples/warn-missing-iife-name/main.js

@@ -0,0 +1 @@
+export const x = 42;

test/misc/write-bundle.js

@@ -25,42 +25,6 @@ describe('bundle.write()', () => {
 			});
 	});
 
-	it('expects output.name for IIFE and UMD bundles', () => {
-		let bundle;
-
-		return rollup
-			.rollup({
-				input: 'x',
-				plugins: [
-					{
-						resolveId: () => 'test',
-						load: () => 'export var foo = 42;'
-					}
-				]
-			})
-			.then(rollupInstance => {
-				bundle = rollupInstance;
-				return bundle.generate({
-					format: 'umd'
-				});
-			})
-			.catch(err => {
-				assert.throws(() => {
-					throw err;
-				}, /You must supply "output\.name" for UMD bundles/);
-			})
-			.then(() => {
-				return bundle.generate({
-					format: 'iife'
-				});
-			})
-			.catch(err => {
-				assert.throws(() => {
-					throw err;
-				}, /You must supply "output\.name" for IIFE bundles/);
-			});
-	});
-
 	it('throws on es6 format', () => {
 		return rollup
 			.rollup({