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@here.build/error-invariant

v0.9.0

Published

Global Error.invariant assertion helper (augments ErrorConstructor; TypeError.invariant resolves via constructor prototype inheritance)

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Links

Git

Maintainers

merkle_bonsaimerkle_bonsai

Keywords

Readme

@here.build/error-invariant

A side-effect import that installs a global Error.invariant(condition, message) assertion helper.

Install

pnpm add @here.build/error-invariant

Usage

Import once (for the side effect) — typically at an entry point:

import "@here.build/error-invariant";

Error.invariant(user != null, "user is required");
// throws an Error when the condition is falsy

TypeError.invariant(typeof x === "number", "x must be a number");
// throws a TypeError — the *receiver's* type

invariant resolves on Error and every subclass via the constructor prototype chain, and throws an instance of the constructor it was called on (MyError.invariant(...) throws a MyError). When the condition holds, it narrows the type for the rest of the scope.

⚠️ Global side effect. Importing this package mutates the global Error constructor (and its subclasses). That is its entire purpose — do not configure your bundler to tree-shake the import away.

License

MIT