@sinonjs/formatio

This package does one thing: format JavaScript objects into readable strings. The API is straightforward—essentially `formatio.ascii(obj)` for most cases. It handles circular references well and produces cleaner output than JSON.stringify for debugging. However, the learning experience is hampered by sparse documentation. The README provides basic usage but lacks examples for edge cases or customization options.

Error messages are minimal, which can be frustrating when dealing with complex objects. When something doesn't format as expected, you're left inspecting the source code. Community support is practically non-existent—Stack Overflow has almost no mentions, and GitHub issues show slow response times. The package is part of the Sinon.js ecosystem but feels like an afterthought in terms of maintenance.

For simple object formatting needs, it works fine once you understand the basics. But if you need anything beyond default behavior or run into issues, you'll be on your own. Consider using Node's built-in `util.inspect()` or `console.dir()` unless you specifically need formatio's output style.

In practice, @sinonjs/formatio is a basic object formatting library primarily used internally by Sinon.js for test output. It converts objects, arrays, and primitives into human-readable strings with some configurability around depth and indentation. The API is straightforward - you call `formatio.ascii.func(object)` and get a string back.

From an operations perspective, it's lightweight with minimal overhead, no external dependencies, and predictable memory usage since it's just string manipulation. However, it offers zero observability hooks, no streaming support for large objects, and will happily consume memory formatting deeply nested structures without proper safeguards beyond basic depth limiting.

The last release in early 2021 raises concerns about ongoing maintenance. For production logging, you're better served by dedicated logging libraries with proper serialization, circular reference handling, and performance optimizations. This feels purpose-built for test output formatting rather than production use, which is fine if that's your use case, but the name and description don't make that obvious.

This is primarily an internal utility extracted from SinonJS for formatting objects into human-readable strings. It does its job for test output formatting, but it's essentially frozen in time since early 2021. The formatting logic handles circular references safely, which prevents infinite loops, but the library lacks modern input validation and has minimal security hardening for untrusted data.

From a security perspective, the main concern is using this on untrusted objects. While it won't crash on circular references, it will eagerly traverse and stringify object properties, which could expose sensitive data in error messages or logs if you're not careful. There's no built-in sanitization, property filtering, or depth limiting beyond basic circular detection. The library assumes you're formatting test fixtures, not user input.

Dependency-wise, it's relatively clean with minimal transitive dependencies, which reduces supply chain risk. However, the lack of recent maintenance means you won't see timely responses to any discovered vulnerabilities. For test output in controlled environments, it's adequate. For anything touching production data or user input, consider alternatives with active maintenance and explicit security features.