minimalistic-assert

minimalistic-assert is a tiny, dependency-free assertion utility for JavaScript. It exposes a single assert(value, message) function that throws an Error when the given value is falsy, plus an assert.equal(left, right, message) helper for loose (!=) equality checks — both with sensible default error messages when none is supplied.

The entire implementation is a single ~10-line file with no runtime dependencies, which is why it shows up as a transitive dependency inside widely-used libraries such as elliptic, bn.js, and asn1.js: those projects need internal invariant checks without pulling in Node’s built-in assert module, which browser bundlers would otherwise have to polyfill.

What You Get

• A single exported assert(value, message) function that throws an Error (with a default or custom message) when value is falsy.
• An assert.equal(left, right, message) helper that throws when its two arguments fail a loose (!=) equality comparison.
• Zero runtime dependencies and a footprint of roughly 250 bytes, keeping it safe to bundle into other libraries.

Common Use Cases

• Library authors targeting both Node and the browser use it in place of Node’s built-in assert to avoid the polyfill bundlers would otherwise add.
• Cryptography and encoding libraries like elliptic, bn.js, and asn1.js use it to guard internal invariants on input data.
• Any small module that needs a quick loose-equality check without importing a heavier assertion library.

Under The Hood

Architecture The module has no architecture to speak of by design: a single index.js file exports one function, assert, which is extended with an assert.equal property. There are no internal layers, no configuration, and no state — calling the exported function either returns silently or throws an Error immediately, making the control flow trivial to trace end to end.

Tech Stack The package is plain, untranspiled JavaScript (CommonJS module.exports) with no build step, no bundler configuration, and no runtime dependencies declared in package.json. It targets any JavaScript environment capable of running plain ES5-style syntax, which is part of why it is safe to embed inside both Node libraries and browser bundles.

Code Quality There are no test files in the repository, and the package.json test script is a placeholder that exits with an error. There is no linter or CI configuration. Given the module’s size (two small functions, no branching beyond simple truthy/equality checks), the surface area for bugs is minimal, but this is a case of the implementation being simple rather than being verified by tooling.

API Design The public API is about as minimal as an assertion library can be: one callable default export plus one attached method, both taking a value (or pair of values) and an optional message. There is no configuration, no setup, and no boilerplate required to start using it — require('minimalistic-assert') and call it. The tradeoff is that documentation is limited to a two-line README, so behavior (e.g., that assert.equal uses loose != rather than strict !==) must be discovered by reading the ~10-line source.