The util.is* functions introduced in Node v0.12.
util.is*
Common JavaScript/TypeScript helper functions for better minification
Test if a value is a regular expression.
Test if a value is a regular expression string.
Utilities to get and check variable types (isString, isPlainObject, isRegExp, etc)
Lightweight debugging utility for Node.js and the browser
Lodash modular utilities.
React is a JavaScript library for building user interfaces.
A querystring parser that supports nesting and arrays, with a depth limit
Higher-order functions and common patterns for asynchronous code
Babel compiler core.