@zerodep/is.error v0.2.0
@zerodep/is.error
A utility to determine if a value is an Error (or instance of the Error class).
tl;dr
A short explanation / quick reference:
import { isError } from '@zerodep/is.error';
isError(new Error()); // true
isError('a string'); // false
Table of Contents
Install
This utility is available from multiple @zerodep packages, enabling developers to select the most appropriately sized package (for both kb and capability) for different use cases. We believe one size does not fit all or most. See @zerodep/app, @zerodep/utils and @zerodep/is.
For Server & Build Tooling
For Node, or when compiling via babel, rollup, swc, tsc, webpack, etc... these are the instructions for you.
// all @zerodep features, capabilities and utilities
npm install @zerodep/app
// entire set of @zerodep utilities
npm install @zerodep/utils
// all @zerodep "is" utilities
npm install @zerodep/is
// only the is.error utility
npm install @zerodep/is.error
Of course, you may use yarn
, pnpm
, or the package manager of your choice. Only npm
examples are shown for brevity.
Browser Direct
If you are using the script directly in a browser via a <script>
tag or importing it into your own scripts, these are the instructions for you. We support both ESM and UMD formats.
<!-- for ES Modules (ESM) -->
<script type="module">
import { isError } from 'https://cdn.jsdelivr.net/npm/@zerodep/is.error/esm.js';
// ...your code here
</script>
<!-- OR -->
<!-- for Universal Modules (UMD) - all @zerodep functions are in the global "zd" namespace -->
<script src="https://cdn.jsdelivr.net/npm/@zerodep/is.error/umd.js"></script>
<script>
// example of "zd" prefix
const result = zd.isError(new SyntaxError('message goes here'));
</script>
This package may be found on both jsDelivr and unpkg in UMD, ESM and CJS formats.
How to Use
This package exports the following:
- Functions
isError
- a function to test if a provided value is anError
(or instance thereof)
Signature
// typescript declaration
declare const isError: (value: any) => boolean;
Examples
All examples assume ESM or CJS packages. If using a UMD package remember to prefix with the zd namespace, e.g. zd.isError(...)
.
// import from the most appropriate @zerodep package for your needs / specific use case (see the Install section above)
import { isError } from '@zerodep/is.error';
isError(new Error()); // true
// strings
isError(''); // false
isError('a string'); // false
// integers
isError(42); // false
isError(3e8); // false
// floats
isError(-273.15); // false
isError(Math.PI); // false
// number-ish
isError(Number.POSITIVE_INFINITY); // false
isError(NaN); // false
// bigints
isError(8675309n); // false
// object literals
isError({}); // false
isError({ a: 'one', b: 'two' }); // false
// arrays
isError([]); // false
isError([1, 2, 3]); // false
isError(['a', 'b', 'c']); // false
// booleans
isError(true); // false
isError(false); // false
// other
isError(/^$\d{7}/g); // false
isError(new Date()); // false
isError(new Date('2022-02-24')); // false
isError(new Set()); // false
isError(new Set([1, 2, 3])); // false
isError(new Map()); // false
isError(new Map([['a', 1]])); // false
isError(Symbol()); // false
isError(() => {}); // false
// nothing
isError(null); // false
isError(undefined); // false
Advantages of @zerodep Packages
We help make source code more readable, more secure, faster to craft, less likely to have hidden defects, and easier to maintain.
- Zero npm dependencies - completely eliminates all risk of supply-chain attacks, decreases
node_modules
folder size - Fully typed - typescript definitions are provided for every package for a better developer experience
- Semantically named - package and method names are easy to grok, remember, use, and read
- Documented - actually useful documentation with examples and helpful tips
- Intelligently Packaged - multiple npm packages of different sizes available allowing a menu or a-la-carte composition of capabilities
- 100% Tested - all methods and packages are fully unit tested
- ESM & CJS - has both ecmascript modules and common javascript exports, both are fully tree-shakable
- CDN Available - available on fast content delivery networks in UMD, CJS and ESM formats
- FP Inspired - gently opinionated to encourage functional programming style for cleaner and more maintainable software
- Predictably Versioned - semantically versioned for peace-of-mind upgrading, this includes changelogs
- MIT Licensed - permissively licensed for maximum usability
Support
All @zerodep packages are built for the ES2020 specification. Should you need to support older environments you will need to add appropriate polyfills. All packages are tested on the following platforms/browsers:
Browsers
- Chrome - last 2 major versions
- Firefox - last 2 major versions
- Safari - last 2 major versions
- Edge - last 2 major versions
- Android - last 2 major versions
- iOS - last 2 major versions
Node
- v16.x - Gallium LTS
- v14.x - Fermium LTS
It is likely the package will work on other technologies and version, however development and testing effort is only spent on the above.
Semver
All @zerodep packages, including this one, adhere to Semantic Versioning practices:
- major versions: correlates with breaking changes to one or more method signatures
- minor versions: includes addition of new functionality or backwards-compatible software improvements
- patch versions: are reserved for copy changes, documentation enhancements and bug fixes
The above said, a security best practice is to pin your software packages to specific versions and only upgrade to more recent releases after careful inspection of any CHANGELOG, release notes and all software changes.