es-typeof

A robust ponyfill for the JavaScript typeof operator. It replicates the exact logic of the native typeof operator while ensuring stability across different environments and realms.

Installation

npm install es-typeof

Usage

var typeOf = require("es-typeof")

typeOf(undefined)     // "undefined"
typeOf(null)          // "object"
typeOf(true)          // "boolean"
typeOf(42)            // "number"
typeOf("hello")       // "string"
typeOf(Symbol("foo")) // "symbol"
typeOf(BigInt(10))    // "bigint"
typeOf(function() {}) // "function"
typeOf({})            // "object"
typeOf([])            // "object"

Why use this instead of native typeof?

While it behaves the same as the typeof keyword, this library is built using get-intrinsic and call-bound. This makes it resistant to environments where global prototypes or constructors have been modified. It also ensures that functions like AsyncFunction and GeneratorFunction are consistently identified even in older or exotic engines.

Testing

The library includes a comprehensive test suite covering primitives, modern types (Symbols/BigInts), and various function types.

node test.js

License

Unlicense