The Quest for Accurate Array Verification in JavaScript

A Surprising Lack of Literature

When working on a recent side project, I encountered an intriguing challenge: validating whether a user’s input was indeed an array, rather than another type of object that could potentially disrupt my algorithm’s complex control flow. Despite the abundance of solutions available, I was surprised to find a scarcity of literature to guide developers in making informed decisions.

Top Three Solutions: A Comparison

After researching and analyzing various metrics, including performance, scalability, maintainability, interoperability, debuggability, readability, and web-scaleability, I identified the top three solutions:

1. isarray

isarray is an excellent npm package that accurately detects whether its given argument is an array. Although its README states that it’s intended for older browsers and deprecated Node.js versions, I found it works well with new browsers and the latest version of Node.

• Pros:
  • Concise, highly-expressive syntax
  • Works well with MongoDB
  • Excellent ROI (only 2-month payback period)
• Cons:
  • No 3rd party plugin ecosystem
  • 3 open GitHub issues

2. is-array

is-array takes a different approach to JavaScript array verification, opting for a hyphen instead of an empty string between “is” and “array” in the package title. It offers improved readability while providing the majority of the expected functionality.

• Pros:
  • It’s cool because it’s less popular
• Cons:
  • Longer name means larger source code (slower Git pushes, less free hard drive space, etc.)
  • Permissive MIT license means a large company could Embrace, Extend, and Extinguish it

3. Array.isArray()

Array.isArray() is a built-in JavaScript method introduced with the ES5 standard. It’s a last resort, suitable only when 3rd party modules are not allowed (enterprise security constraints, use on a desert island, etc.).

• Pros:
  • At least 95% accurate
• Cons:
  • Not on npm
  • Not supported in Opera 4
  • Will throw an error if you try to import it with webpack

In summary, each solution has its strengths and weaknesses. The choice ultimately depends on your specific needs and priorities.