@thi.ng/errors

[!NOTE] This is one of 212 standalone projects, maintained as part of the @thi.ng/umbrella monorepo and anti-framework.

🚀 Please help me to work full-time on these projects by sponsoring me on GitHub. Thank you! ❤️

• About
• Status
• Installation
• Dependencies
• Usage examples
• API
  • Environment variables
• Authors
• License

About

Custom error types and error factory functions.

This package defines the following error types & helper functions to throw them:

• AssertionError
• IllegalArgumentError
• IllegalArityError
• IllegalStateError
• OutOfBoundsError
• UnsupportedOperationError

Custom error types can be easily defined using defError().

Status

STABLE - used in production

Search or submit any issues for this package

Installation

yarn add @thi.ng/errors

ESM import:

import * as err from "@thi.ng/errors";

Browser ESM import:

<script type="module" src="https://esm.run/@thi.ng/errors"></script>

JSDelivr documentation

For Node.js REPL:

const err = await import("@thi.ng/errors");

Package sizes (brotli'd, pre-treeshake): ESM: 849 bytes

Dependencies

None

Usage examples

One project in this repo's /examples directory is using this package:

Description	Live demo	Source
GPU-based data reduction using thi.ng/shader-ast & WebGL multi-pass pipeline	Demo	Source

API

Generated API docs

import * as err from "@thi.ng/errors";

err.illegalArity(3)
// Error: illegal arity: 3

err.illegalArgs("expected foo");
// Error: illegal argument(s): expected foo

err.illegalState("oops");
// Error: illegal state: oops

err.unsupported("TODO not yet implemented")
// Error: unsupported operation: TODO not yet implemented

// define custom error
const MyError = err.defError(
    () => "Eeek... ",
    (x) => x + " is not allowed!"
);

try {
    throw new MyError(23);
} catch(e) {
    console.warn(e.message);
    console.log(e instanceof Error);
}
// Eeek... 23 is not allowed!
// true

Environment variables

The UMBRELLA_ASSERTS or VITE_UMBRELLA_ASSERTS env variables are used to control the behavior of the assert() function in production builds: If either is set (to a non-empty string), the function will always be enabled. Otherwise (by default), assert() will be disabled for production builds, i.e. if process.env.NODE_ENV === "production".

Authors

• Karsten Schmidt

If this project contributes to an academic publication, please cite it as:

@misc{thing-errors,
  title = "@thi.ng/errors",
  author = "Karsten Schmidt",
  note = "https://thi.ng/errors",
  year = 2018
}

License

© 2018 - 2025 Karsten Schmidt // Apache License 2.0

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