Beautiful, Rust-style error reporting for Node.js with source code context and syntax highlighting
npm install error-less> Beautiful, Rust-style error reporting for Node.js
Transform noisy Node.js stack traces into beautiful, actionable error reports with source code context—just like Rust, Next.js, and other modern frameworks.
- Zero Configuration: Just import and errors become beautiful
- Source Code Context: See the exact line that caused the error with surrounding code
- Syntax Highlighting: Code snippets are colorized for readability
- Source Map Support: Works with TypeScript and transpiled code
- Smart Filtering: Focuses on your code, not node_modules
- Zero Runtime Cost: Only activates when errors are thrown
- Graceful Fallback: Never crashes your app—falls back to standard traces if needed
Before (Standard Node.js):
``
TypeError: Cannot read properties of undefined (reading 'name')
at getUser (/app/src/services/user.ts:45:12)
at processRequest (/app/src/handlers/api.ts:23:8)
at /app/src/index.ts:67:5
After (error-less):
`
TypeError: Cannot read properties of undefined (reading 'name')
→ ./src/services/user.ts:45:12
43 │ function getUser(id: string) {
44 │ const user = users.get(id);
> 45 │ return user.name;
│ ^^^
46 │ }
47 │
tip: Verify the value type matches what the operation expects
`
`bash`
npm install error-less
Just import at the top of your entry file:
`typescript
import 'error-less/register';
// Your code here...
throw new Error('Something went wrong!');
`
For more control:
`typescript
import { install, configure } from 'error-less';
install({
showFullStack: true,
contextLinesBefore: 3,
contextLinesAfter: 3,
});
`
`typescript
import { formatError } from 'error-less';
try {
riskyOperation();
} catch (error) {
console.error(formatError(error));
// Handle the error...
}
`
`typescript
import { install } from 'error-less';
install({
// Lines of context before the error line (default: 2)
contextLinesBefore: 2,
// Lines of context after the error line (default: 2)
contextLinesAfter: 2,
// Enable source map resolution (default: true)
enableSourceMaps: true,
// Filter out node_modules frames (default: true)
filterNodeModules: true,
// Show full stack trace after code frame (default: false)
showFullStack: false,
// Force colors on/off (default: auto-detected)
colors: true,
// Custom frame filter
frameFilter: (frame) => !frame.filePath.includes('test'),
});
`
#### install(config?: ErrorLessConfig): void
Installs the custom stack trace handler.
#### uninstall(): void
Restores the original stack trace behavior.
#### configure(config: Partial
Updates configuration without reinstalling.
#### formatError(error: Error): string
Returns a formatted error string. Useful for try/catch blocks.
#### formatThrown(thrown: unknown): string
Formats any thrown value (not just Error instances).
#### isEnabled(): boolean
Returns whether error-less is currently active.
#### getErrorFrames(error: Error): ParsedFrame[]
Get parsed stack frames for advanced usage.
#### clearFileCache(): void
Clear the file content cache.
#### clearSourceMapCache(): void
Clear the source map consumer cache.
error-less is written in TypeScript and provides full type definitions.
`typescript`
import type { ErrorLessConfig, ParsedFrame } from 'error-less';
error-less automatically detects and uses source maps:
1. Inline source maps: Embedded in the compiled file as base64
2. External source maps: .map files alongside compiled filessourcesContent
3. Embedded source content: Uses from maps when available
For TypeScript, ensure your tsconfig.json includes:
`json`
{
"compilerOptions": {
"sourceMap": true
}
}
error-less hooks into V8's Error.prepareStackTrace API. When an error's .stack` property is accessed:
1. The custom handler receives structured stack frame data
2. Frames are parsed to extract file paths, line numbers, and columns
3. Source maps are checked for original source locations
4. Source files are read and code context is extracted
5. A beautiful, syntax-highlighted output is generated
This approach has zero performance impact during normal execution—code only runs when an error is thrown and its stack is accessed.
| Feature | error-less | pretty-error | youch |
|---------|-----------|--------------|-------|
| Zero config | ✅ | ❌ | ❌ |
| Source code display | ✅ | ❌ | ✅ |
| Source map support | ✅ | ❌ | ✅ |
| Syntax highlighting | ✅ | ❌ | ❌ |
| Smart filtering | ✅ | ✅ | ✅ |
| Pure terminal output | ✅ | ✅ | ❌ (HTML) |
MIT