Registry / http-networking / capability

capability

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library0.2.5jsnpmunverified

capability.js is a lightweight JavaScript library designed for detecting specific environmental capabilities, primarily focusing on browser features. Released in 2016, its current stable version is 0.2.5, indicating it has not seen significant development since its initial release. The library allows developers to define custom capability tests using a simple API and then query or enforce these capabilities. Unlike comprehensive feature detection libraries like Modernizr, `capability.js` provides a minimalist approach for defining and checking individual features such as `Object.create`, `Array.prototype.forEach`, or `Function.prototype.bind`. Its release cadence appears to be inactive, with no recent updates. It relies on CommonJS modules and requires a bundler like Webpack or Browserify for use in browser environments, as native ES modules were not widely supported when it was developed. This makes it less suitable for modern projects that typically use native ES modules and rely on built-in browser feature detection or more actively maintained polyfill solutions.

http-networking
github ↗package ↗
Install & Compatibility
Where this runs
tested against v? · npm install
Install × environment matrix
Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux
musl
node 18–226 runs
build_error
glibc
node 18–226 runs
build_error
Code
Verified usage

Verified import paths — ran on the pinned version, not inferred.

The library primarily uses CommonJS `require()` syntax as it was released in 2016. Direct ESM `import` is not supported without a CommonJS-to-ESM transpilation step.

const capability = require('capability');

Used for defining new capabilities. Access through the main `capability` object.

const capability = require('capability'); capability.define('myFeature', () => /* test logic */);

The `test` function is a method of the main `capability` object, not a named export. It can also be invoked as `capability(name)` for brevity.

const capability = require('capability'); const isSupported = capability.test('Object.create');

Specific capability groups (like ES5 features) can be 'required' as sub-modules to automatically run their `check` functions, throwing an error if requirements are not met.

require('capability/es5');

Demonstrates how to define, test, and enforce capabilities, including using the shorthand `capability()` and loading specific capability modules.

const capability = require('capability'); // Define a custom capability capability.define('XMLHttpRequest', function () { return typeof XMLHttpRequest !== 'undefined'; }); // Test if a capability is supported const hasObjectCreate = capability.test('Object.create'); console.log(`Object.create is supported: ${hasObjectCreate}`); const hasCustomFeature = capability('XMLHttpRequest'); // Shorthand for capability.test console.log(`XMLHttpRequest is supported: ${hasCustomFeature}`); // Enforce a capability (will throw an error if not supported) try { capability.check('Array.prototype.forEach'); console.log('Array.prototype.forEach is available.'); } catch (error) { console.error(`Error: ${error.message}`); } // Load a specific capability group to enforce its requirements try { require('capability/es5'); // This will run checks for all ES5 capabilities defined in the library console.log('Environment meets ES5 requirements (via /es5 module).'); } catch (error) { console.error(`Error loading ES5 capabilities: ${error.message}`); }
Debug
Known footguns
gotchaThis library was last updated in 2016 and is likely unmaintained. Use in new projects is not recommended, and direct feature detection or actively maintained polyfill libraries are generally preferred for modern web development.
breakingThe library primarily uses CommonJS `require()` syntax. Attempting to use ES module `import` syntax directly will fail in most environments without a build step that handles CommonJS modules.
gotchaFor browser usage, the library explicitly states it requires a 'node module loader' like Browserify or Webpack. It is not designed for direct inclusion via `<script>` tags without a bundling step.
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Version history

Breaking-change detection hasn't run for this library yet.

Audit
Security & dependencies

CVE tracking and dependency tree are planned for a later release.

Agent activity
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Resources
githubhttps://github.com/inf3rno/capability ↗
packagehttps://www.npmjs.com/package/capability ↗