stackblitz-common-errors

npx skills add jeremylongshore/claude-code-plugins-plus-skills --skill stackblitz-common-errors --agent claude-code

Same command for any agent — swap --agent for codex, cursor, copilot.

# StackBlitz Common Errors ## Error Reference ### SharedArrayBuffer is not defined **Cause:** Missing cross-origin isolation headers. ``` Cross-Origin-Embedder-Policy: require-corp Cross-Origin-Opener-Policy: same-origin ``` **Fix:** Add both headers to your server. In Vite: `server.headers` config. ### Failed to boot WebContainer **Cause:** Only one WebContainer instance allowed per page. ```typescript // BAD: Multiple boot calls const wc1 = await WebContainer.boot(); const wc2 = await WebContainer.boot(); // Fails! // GOOD: Singleton pattern let instance: WebContainer | null = null; async function getWC() { if (!instance) instance = await WebContainer.boot(); return instance; } ``` ### npm install hangs or fails **Cause:** Large dependency tree or network issue in WebContainer. ```typescript // Use --prefer-offline and minimal deps const proc = await wc.spawn('npm', ['install', '--prefer-offline']); const code = await proc.exit; if (code !== 0) { console.error('Install failed, retrying...'); const retry = await wc.spawn('npm', ['install']); await retry.exit; } ``` ### server-ready event never fires **Cause:** Application not listening on a port. ```typescript // Ensure your app c