isarray
A polyfill for Array.isArray to support older browsers and deprecated Node.js versions.
What is isarray?
isarray is a JavaScript polyfill that provides the `Array.isArray` method for environments where it is not natively supported. It solves the problem of inconsistent array type checking in older browsers and deprecated Node.js versions by implementing the standard ECMAScript specification. The package allows developers to use modern JavaScript features while maintaining compatibility with legacy systems.
JavaScript developers who need to support older browsers (like IE8-IE10) or deprecated Node.js versions in their applications, particularly those working on legacy codebases or projects with broad compatibility requirements.
Developers choose isarray because it provides a minimal, reliable implementation of a standard API without unnecessary dependencies. It is specifically designed for compatibility scenarios where native `Array.isArray` is unavailable, ensuring consistent behavior across different JavaScript environments.
Overview
Array#isArray for older browsers.
Use Cases
Best For
- Adding array type checking to legacy web applications
- Supporting older browsers in JavaScript libraries
- Maintaining compatibility with deprecated Node.js versions
- Ensuring consistent behavior in polyfill-dependent projects
- Testing array detection in cross-browser testing scenarios
- Building tools that need to work across multiple JavaScript runtime versions
Not Ideal For
- Projects targeting only modern browsers with native Array.isArray support (e.g., Chrome 5+, Firefox 4+, Edge 12+)
- Applications using JavaScript frameworks that automatically handle polyfills via tools like Babel or core-js
- New codebases that can enforce minimum browser versions to avoid legacy dependencies entirely
Pros & Cons
Pros
Implements the exact ECMAScript specification for Array.isArray, ensuring reliable and consistent array detection across all supported environments, as per the README's emphasis on following MDN documentation.
Provides Array.isArray functionality for older browsers like IE8-IE10 that lack native support, directly addressing the project's goal of compatibility with deprecated systems.
A lightweight package with no dependencies, avoiding unnecessary bloat and keeping the project focused on a single utility, as highlighted in the README's philosophy.
Works with deprecated Node.js versions that don't include built-in Array.isArray, enabling consistent array checking in older server-side environments.
Cons
Only polyfills Array.isArray, which can lead to dependency sprawl if multiple polyfills are needed for broader compatibility, adding maintenance overhead.
Requires the use of bundlers like browserify for browser applications, as noted in the README, adding setup complexity compared to more integrated polyfill solutions.
As browser and Node.js support for Array.isArray becomes near-universal, the need for this polyfill diminishes, potentially making it obsolete in modern development workflows.
Frequently Asked Questions
Related Projects
array-includesArray.prototype.includes spec-compliant polyfill
Array.prototype.findSimple ES6 Array.prototype.find polyfill for older environments.
array.prototype.flatmapAn ESnext spec-compliant `Array.prototype.flatMap` shim/polyfill/replacement that works as far down as ES3.
array-fromA ponyfill for the ES 2015 `Array.from()`
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