@thi.ng/errors

What is @thi.ng/errors?

@thi.ng/errors is a utility library for creating and handling custom error types in JavaScript. It provides a set of predefined error classes and functions to simplify error handling and improve code readability.

What are @thi.ng/errors's main functionalities?

Custom Error Classes

This feature allows you to create and use custom error classes like IllegalArgumentError and IllegalStateError to handle specific error conditions in your code.

const { IllegalArgumentError, IllegalStateError } = require('@thi.ng/errors');

function checkAge(age) {
  if (age < 0) {
    throw new IllegalArgumentError('Age cannot be negative');
  }
  if (age > 120) {
    throw new IllegalStateError('Age seems unrealistic');
  }
  return 'Age is valid';
}

try {
  console.log(checkAge(-5));
} catch (e) {
  console.error(e.message);
}

Predefined Error Types

The package provides predefined error types like UnsupportedOperationError to handle common error scenarios in a standardized way.

const { UnsupportedOperationError } = require('@thi.ng/errors');

function notImplemented() {
  throw new UnsupportedOperationError('This operation is not supported');
}

try {
  notImplemented();
} catch (e) {
  console.error(e.message);
}

Error Wrapping

The wrapError function allows you to wrap existing errors with additional context, making it easier to debug and understand the root cause of errors.

const { wrapError } = require('@thi.ng/errors');

function riskyOperation() {
  try {
    throw new Error('Something went wrong');
  } catch (e) {
    throw wrapError(e, 'Risky operation failed');
  }
}

try {
  riskyOperation();
} catch (e) {
  console.error(e.message);
}

Other packages similar to @thi.ng/errors

create-error-class

create-error-class is a utility for creating custom error classes in JavaScript. It is similar to @thi.ng/errors in that it allows for the creation of custom error types, but it does not provide predefined error types or error wrapping functionality.

verror

verror is a library for creating and manipulating chained errors. It provides more advanced error wrapping and chaining capabilities compared to @thi.ng/errors, making it suitable for complex error handling scenarios.

custom-error-generator

custom-error-generator is a simple utility for generating custom error classes. It is similar to @thi.ng/errors in terms of creating custom error types but lacks the predefined error types and error wrapping features.

README

[!NOTE] This is one of 199 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: 817 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 - 2024 Karsten Schmidt // Apache License 2.0