typeis-package is a handy npm package that returns the type of the variable passed to it. It's designed to handle most variable types, including custom ones. If nothing is passed, it will return undefined.
You can install the package using npm:
```bash npm i typeis-package ```
Import typeIs from typeis-package, and you can use it to determine the type of most variables.
```javascript import typeIs from 'typeis-package';
const result = typeIs('Hello, World!'); // returns 'string' ```
Here's the core code of the package:
```javascript const typeIs = (input) => { if (input === null) return "null"; if (typeof input !== "object") { return typeof input; } let type = (input?.constructor?.name).toLowerCase(); return type ?? new Error("unknownType"); };
export default typeIs; ```
If a custom object is passed, the type that will be returned is its name in lowercase.
If a promise is abstracted under another name, the package may fail to identify it a promise and return it as the name of it's constructor.
The code doesn't specifically handle typed arrays like Int8Array, Uint8Array, etc., so it will return their constructor names in lowercase.
The code will return "object" for the global object (e.g., window in browsers), which might be what you want, but it's worth being aware of.
```javascript import typeIs from 'typeis-package';
console.log(typeIs(null)); // returns 'null' console.log(typeIs(42)); // returns 'number' console.log(typeIs(new Int8Array())); // returns 'int8array' ```
typeis-package is a versatile tool for identifying variable types in JavaScript. It's simple to use and covers a wide range of use cases. Be mindful of the special cases mentioned above to get the most out of this package.
Feel free to contribute, report issues, or suggest improvements on the GitHub repository.