@zerodep/is.weakmap v0.2.0
@zerodep/is.weakmap
A utility to determine if a value is a WeakMap.
tl;dr
A short explanation / quick reference:
import { isWeakMap } from '@zerodep/is.weakmap';
isWeakMap(new WeakMap()); // true
isWeakMap('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.weakmap utility
npm install @zerodep/is.weakmap
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 { isWeakMap } from 'https://cdn.jsdelivr.net/npm/@zerodep/is.weakset/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.weakset/umd.js"></script>
<script>
// example of "zd" prefix
const result = zd.isWeakMap(new WeakMap());
</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
isWeakMap
- a function to test if a provided value is aWeakMap
Signature
// typescript declaration
declare const isWeakMap: (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.isWeakMap(...)
.
// import from the most appropriate @zerodep package for your needs / specific use case (see the Install section above)
import { isWeakMap } from '@zerodep/is.weakmap';
isWeakMap(new WeakMap()); // true
// strings
isWeakMap(''); // false
isWeakMap('a string'); // false
// integers
isWeakMap(42); // false
isWeakMap(3e8); // false
// floats
isWeakMap(-273.15); // false
isWeakMap(Math.PI); // false
// number-ish
isWeakMap(Number.POSITIVE_INFINITY); // false
isWeakMap(NaN); // false
// bigints
isWeakMap(8675309n); // false
// object literals
isWeakMap({}); // false
isWeakMap({ a: 'one', b: 'two' }); // false
// arrays
isWeakMap([]); // false
isWeakMap([1, 2, 3]); // false
isWeakMap(['a', 'b', 'c']); // false
// booleans
isWeakMap(true); // false
isWeakMap(false); // false
// other
isWeakMap(/^$\d{7}/g); // false
isWeakMap(new Date()); // false
isWeakMap(new Date('2022-02-24')); // false
isWeakMap(new Set()); // false
isWeakMap(new Set([1, 2, 3])); // false
isWeakMap(new Map()); // false
isWeakMap(new Map([['a', 1]])); // false
isWeakMap(Symbol()); // false
isWeakMap(new Error()); // false
isWeakMap(() => {}); // false
// nothing
isWeakMap(null); // false
isWeakMap(undefined); // false
Related Packages
The following @zerodep packages may be helpful or more appropriate for your specific case:
- @zerodep/is.object - checks if a value is an object
- @zerodep/is.map - checks if a value is a Map object
- @zerodep/guard.weakmap - only allows WeakMap objects (throws an error for non-weakmap values), reduces the need to write
if/else
code
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.