Is Packages

is-env can determine the current JavaScript running environment, and now includes 'browser', 'react-native', 'nodejs'.

test whether an object is a DOM image or canvas

A native module for effectively validating if a value is type Number.

Test if something is a Symbol. Works with either native or polyfill Symbols.

Check if a file path is a Markdown file

Is localhost predicate

Returns true if a value is an object and appears to be a valid Templates view object.

JSON isNull method

Check that given value is Generator

check if a key event is undo or redo

Checks if a provided value is a part of the is-that-this package

Check type of given javascript value. Support promises, generators, streams, and native types. Built on [kind-of][] lib.

Checks whether a value is a proxy object

Check if a domain is public

Checks if the given value is null.

Check is complex structure set

cli to tell you if it's independence day

complete type checking for browser and node

Typify your JavaScript functions.

Typified checkers for js primitives and objects for flow.js and typescript