[feat] Friendlier error messages for common config errors (#1910)

sveltejs · Jul 15, 2021 · 53e9285 · 53e9285
1 parent 41da1eb
commit 53e9285
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diff --git a/.changeset/little-boats-allow.md b/.changeset/little-boats-allow.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+feat(config): Friendlier error messages for common errors
diff --git a/packages/kit/src/core/config/index.js b/packages/kit/src/core/config/index.js
@@ -13,6 +13,17 @@ import options from './options.js';
  * @returns {any}
  */
 function validate(definition, option, keypath) {
+	if (typeof option !== 'object') {
+		if (typeof option === 'undefined') {
+			throw new Error(
+				'Your config is missing default exports. Make sure to include "export default config;"'
+			);
+		} else {
+			throw new Error(
+				`Unexpected config type "${typeof option}", make sure your default export is an object.`
+			);
+		}
+	}
 	for (const key in option) {
 		if (!(key in definition)) {
 			let message = `Unexpected option ${keypath}.${key}`;

diff --git a/packages/kit/src/core/config/test/fixtures/export-missing/src/app.html b/packages/kit/src/core/config/test/fixtures/export-missing/src/app.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html lang="en">
+	<head>
+		<meta charset="utf-8" />
+		<link rel="icon" href="/favicon.ico" />
+		<meta name="viewport" content="width=device-width, initial-scale=1" />
+		%svelte.head%
+	</head>
+	<body>
+		<div id="svelte">%svelte.body%</div>
+	</body>
+</html>
diff --git a/packages/kit/src/core/config/test/fixtures/export-missing/svelte.config.js b/packages/kit/src/core/config/test/fixtures/export-missing/svelte.config.js
diff --git a/packages/kit/src/core/config/test/fixtures/export-string/src/app.html b/packages/kit/src/core/config/test/fixtures/export-string/src/app.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html lang="en">
+	<head>
+		<meta charset="utf-8" />
+		<link rel="icon" href="/favicon.ico" />
+		<meta name="viewport" content="width=device-width, initial-scale=1" />
+		%svelte.head%
+	</head>
+	<body>
+		<div id="svelte">%svelte.body%</div>
+	</body>
+</html>
diff --git a/packages/kit/src/core/config/test/fixtures/export-string/svelte.config.js b/packages/kit/src/core/config/test/fixtures/export-string/svelte.config.js
@@ -0,0 +1 @@
+export default 'invalid';
diff --git a/packages/kit/src/core/config/test/index.js b/packages/kit/src/core/config/test/index.js
@@ -71,4 +71,34 @@ test('load default config (esm)', async () => {
 	await testLoadDefaultConfig('default-esm');
 });
 
+test('errors on loading config without default export', async () => {
+	let errorMessage = null;
+	try {
+		const cwd = join(__dirname, 'fixtures', 'export-missing');
+		await load_config({ cwd });
+	} catch (e) {
+		errorMessage = e.message;
+	}
+
+	assert.equal(
+		errorMessage,
+		'Your config is missing default exports. Make sure to include "export default config;"'
+	);
+});
+
+test('errors on loading config with incorrect default export', async () => {
+	let errorMessage = null;
+	try {
+		const cwd = join(__dirname, 'fixtures', 'export-string');
+		await load_config({ cwd });
+	} catch (e) {
+		errorMessage = e.message;
+	}
+
+	assert.equal(
+		errorMessage,
+		'Unexpected config type "string", make sure your default export is an object.'
+	);
+});
+
 test.run();