kind-of

What is kind-of?

The kind-of npm package is a utility library that allows developers to check the type of a given value in JavaScript. It provides a simple API to determine whether a value is a string, number, array, object, function, and other JavaScript types. This can be particularly useful for type checking and validation in applications where type safety is important.

What are kind-of's main functionalities?

Type checking for primitives

This feature allows you to check the type of primitive values such as numbers, strings, and booleans.

"use strict"; const kindOf = require('kind-of'); console.log(kindOf(1)); // 'number' console.log(kindOf('hello')); // 'string' console.log(kindOf(true)); // 'boolean'

Type checking for objects

This feature allows you to check the type of object-based values such as plain objects, arrays, and regular expressions.

"use strict"; const kindOf = require('kind-of'); console.log(kindOf({})); // 'object' console.log(kindOf([])); // 'array' console.log(kindOf(/foo/)); // 'regexp'

Type checking for functions and undefined

This feature allows you to check the type of functions and the undefined value.

"use strict"; const kindOf = require('kind-of'); console.log(kindOf(function () {})); // 'function' console.log(kindOf(undefined)); // 'undefined'

Type checking for null and dates

This feature allows you to check the type of null values and date objects.

"use strict"; const kindOf = require('kind-of'); console.log(kindOf(null)); // 'null' console.log(kindOf(new Date())); // 'date'

Other packages similar to kind-of

type-check

The 'type-check' package offers a similar functionality to 'kind-of' by allowing type assertions and checks. It provides a mini language to specify the types of values and can validate against those specifications.

is

The 'is' package is another utility library that provides type checking functions. It has a wider range of type checks available, including checks for specific JavaScript environments like the browser or Node.js.

check-types

The 'check-types' package provides a set of predicates for type checking. It has a fluent API and includes additional checks for min/max values, empty strings, and arrays, which are not directly available in 'kind-of'.

README

kind-of

Get the native type of a value.

Install

Install with npm:

npm i kind-of --save-dev

Run tests

npm test

Usage

var kindOf = require('kind-of');

kindOf(undefined);
//=> 'undefined'

kindOf(null);
//=> 'null'

kindOf(true);
//=> 'boolean'

kindOf(false);
//=> 'boolean'

kindOf(new Boolean(true));
//=> 'boolean'

kindOf(42);
//=> 'number'

kindOf(new Number(42));
//=> 'number'

kindOf("string");
//=> 'string'

kindOf(arguments);
//=> 'arguments'

kindOf({});
//=> 'object'

kindOf(new Test());
//=> 'object'

kindOf(new Date());
//=> 'date'

kindOf([]);
//=> 'array'

kindOf([1, 2, 3]);
//=> 'array'

kindOf(new Array());
//=> 'array'

kindOf(/[\s\S]+/);
//=> 'regexp'

kindOf(new RegExp('^' + 'foo$'));
//=> 'regexp'

kindOf(function () {});
//=> 'function'

kindOf(new Function());
//=> 'function'

Author

Jon Schlinkert

• github/jonschlinkert
• twitter/jonschlinkert

License

Copyright (c) 2014 Jon Schlinkert, contributors.
Released under the MIT license

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This file was generated by verb-cli on October 26, 2014.

Changelog

[0.1.2] - 2014-10-26

• return typeof value if it's not an object. very slight speed improvement
• use .slice
• adds benchmarks