add script for checking js extension in imports (thx copilot)

svelteplot · gka · Jun 18, 2025 · Jun 18, 2025 · Jun 18, 2025 · Jun 18, 2025
commit 9523634479d46316f02d3fdbc32ab6f6a335f8c4
diff --git a/package.json b/package.json
@@ -19,7 +19,8 @@
         "prepack": "npx svelte-package",
         "release-next": "npm version prerelease --preid next && npm publish && git push && git push --tags && sleep 1 && npm dist-tag add svelteplot@$(npm view . version) next",
         "docs": "npm run build && cd build && rsync --recursive . vis4.net:svelteplot/alpha0/",
-        "screenshots": "node screenshot-examples.js"
+        "screenshots": "node screenshot-examples.js",
+        "check-js-extensions": "node scripts/check-js-extensions.js src"
     },
     "exports": {
         ".": {

diff --git a/scripts/check-js-extensions.js b/scripts/check-js-extensions.js
@@ -0,0 +1,138 @@
+#!/usr/bin/env node
+/* eslint-disable no-console */
+
+/**
+ * This script checks for missing .js extensions in import statements.
+ * It helps identify issues with ESM imports where TypeScript requires .js extensions.
+ */
+
+import { readFile, readdir, stat } from 'fs/promises';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+// Convert file:// URLs to paths
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+// Regular expressions to match import statements without .js extensions
+const regexImportFrom =
+    /import\s+(?:type\s+)?(?:{[^}]*}|\*\s+as\s+[^;]*|[^;{]*)\s+from\s+['"]([^'"]*)['"]/g;
+const regexExportFrom =
+    /export\s+(?:type\s+)?(?:{[^}]*}|\*\s+as\s+[^;]*)\s+from\s+['"]([^'"]*)['"]/g;
+
+// Skip node_modules and build directories
+const excludedDirs = ['node_modules', 'build', '.svelte-kit', 'dist', '.git', 'examples', 'tests'];
+
+// Only check certain file types
+const includedExtensions = ['.ts', '.js', '.svelte'];
+
+// Paths that should have .js extensions (relative paths and alias paths)
+const shouldHaveJsExtension = (importPath) => {
+    // Skip Svelte imports
+    if (importPath.endsWith('.svelte')) return false;
+
+    // Skip npm package imports (those that don't start with . or /)
+    if (
+        !importPath.startsWith('.') &&
+        !importPath.startsWith('/') &&
+        !importPath.startsWith('$lib')
+    )
+        return false;
+
+    // Skip imports with extensions already
+    if (path.extname(importPath)) return false;
+
+    return true;
+};
+
+async function* walkDirectory(dir) {
+    const entries = await readdir(dir, { withFileTypes: true });
+
+    for (const entry of entries) {
+        const fullPath = path.join(dir, entry.name);
+
+        if (entry.isDirectory()) {
+            if (!excludedDirs.includes(entry.name)) {
+                yield* walkDirectory(fullPath);
+            }
+        } else if (includedExtensions.includes(path.extname(entry.name))) {
+            yield fullPath;
+        }
+    }
+}
+
+async function checkFile(filePath) {
+    const content = await readFile(filePath, 'utf8');
+    const issues = [];
+
+    // Find all import statements
+    let match;
+
+    // Check import statements
+    regexImportFrom.lastIndex = 0;
+    while ((match = regexImportFrom.exec(content)) !== null) {
+        const importPath = match[1];
+        if (shouldHaveJsExtension(importPath)) {
+            issues.push({
+                line: content.substring(0, match.index).split('\n').length,
+                importPath,
+                statement: match[0]
+            });
+        }
+    }
+
+    // Check export from statements
+    regexExportFrom.lastIndex = 0;
+    while ((match = regexExportFrom.exec(content)) !== null) {
+        const importPath = match[1];
+        if (shouldHaveJsExtension(importPath)) {
+            issues.push({
+                line: content.substring(0, match.index).split('\n').length,
+                importPath,
+                statement: match[0]
+            });
+        }
+    }
+
+    return { filePath, issues };
+}
+
+async function main() {
+    const rootDir = process.argv[2] || process.cwd();
+    console.log(`Checking for missing .js extensions in ${rootDir}...\n`);
+
+    let totalIssues = 0;
+    let filesWithIssues = 0;
+
+    for await (const filePath of walkDirectory(rootDir)) {
+        const { issues } = await checkFile(filePath);
+
+        if (issues.length > 0) {
+            console.log(`\x1b[33m${filePath}\x1b[0m`);
+            filesWithIssues++;
+
+            for (const issue of issues) {
+                totalIssues++;
+                console.log(
+                    `  Line ${issue.line}: Missing .js extension in import: ${issue.importPath}`
+                );
+                console.log(`    ${issue.statement}`);
+            }
+            console.log('');
+        }
+    }
+
+    if (totalIssues === 0) {
+        console.log('\x1b[32mNo missing .js extensions found!\x1b[0m');
+    } else {
+        console.log(
+            `\x1b[31mFound ${totalIssues} missing .js extensions in ${filesWithIssues} files.\x1b[0m`
+        );
+        process.exit(1);
+    }
+}
+
+main().catch((err) => {
+    console.error('Error:', err);
+    process.exit(1);
+});