The `verror` library, currently at stable version 1.10.1, provides a set of robust error classes designed for creating richer, more debuggable JavaScript errors. Its core strength lies in implementing Joyent's best practices for error handling, offering features like `printf`-style message formatting for clear, human-readable errors, and sophisticated error chaining. `VError` allows chaining errors while preserving messages from all layers of the call stack, providing a comprehensive diagnostic trail. Conversely, `WError` wraps and chains errors but hides lower-level messages from the top-level error, making it suitable for public API endpoints where internal details should be obscured. The library also includes `SError` for stricter `printf` argument validation and `MultiError` for aggregating errors from parallel operations. While highly functional, its release cadence is slow, with the last major update being several years ago, and it primarily targets CommonJS environments, lacking native ESM support. This makes it a mature, stable choice, though potentially requiring adaptation for modern JavaScript module systems.
npm install verrorVerified import paths — ran on the pinned version, not inferred.
Demonstrates VError's core features including printf-style messages, error chaining, accessing underlying causes, and attaching informational properties, using a file system operation as an example.
Strictly use CommonJS `require()` syntax. For new projects requiring native ESM, consider alternative error handling libraries or a CommonJS wrapper.
Understand the distinction between `VError` (full chain in message) and `WError` (top-level message only). To access full details with `WError`, use `err.fullStack()` or `err.cause()` to traverse the chain programmatically.
Carefully match format specifiers with the corresponding arguments. Ensure the correct number and type of arguments are provided for each specifier in the format string.
For new projects, evaluate if alternatives offering more active maintenance and modern features are more suitable. For existing projects, be aware of its static nature regarding new features or ecosystem changes.
Implement a helper function to traverse the cause chain (e.g., a `while` loop or recursive function) to find a specific cause or collect all causes, reducing verbose access.
Ensure the error object is an instance of a `verror` class and was explicitly created with a `cause`. Use `VError.hasCause(err)` to safely check if an error object has a cause before attempting to access it.
Review the format string in the error constructor and ensure there is a corresponding argument for each format specifier. For example, `new VError('Hello %s')` requires one string argument after the message.Use the CommonJS `require` syntax: `const VError = require('verror');` for the primary class. Other classes like `WError` are accessed as properties (e.g., `VError.WError`). The package does not natively support ESM imports.No dependency data recorded yet.