JSPM

Check if a string is an IP address

Check if a string is an IP address

Validates given IPs (IPv4 and IPv6) using [micromatch][] - glob patterns, RegExp, string or array of globs. If match returns the IP, otherwise null.

Check if a string is an IP address. This is a fork of sindresorhus/is-ip, but with CommonJS support.

Static check if a hostname is a local IP address.

Check whether an IP is in a range

Check if a local or remote port is reachable

Matching IPs using [micromatch][] and [ip-filter][] - glob patterns, RegExp, string or array of globs. Returns matcher function.

A simple Node.js module to check if a TCP port is already bound.

Check if argv has a specific flag

Get the native type of a value.

Returns your remote address from os.networkInterfaces() if available, or false if not.

Check if something is a Node.js stream

Check if the character represented by a given Unicode code point is fullwidth

Returns true if a number or string value is a finite number. Useful for regex matches, parsing, user input, etc.

Check if a path is a file, directory, or symlink

Returns `true` if the given string looks like a glob pattern or an extglob pattern. This makes it easy to create code that only uses external modules like node-glob when necessary, resulting in much faster code execution and initialization time, and a bet

Check if the process is running inside Windows Subsystem for Linux (Bash on Windows)

Returns true if the value is an object and not an array or null.

Returns true if a string has an extglob.

Check if a value is a plain object

Check if a file path is a binary file

type-check allows you to check the types of JavaScript values at runtime with a Haskell like type syntax.

Returns true if an object was created by the `Object` constructor, or Object.create(null).

Detect whether the terminal supports Unicode

Detect the file type of a file, stream, or data

Returns true if a value is a plain object, array or function.

Returns true if a value has the characteristics of a valid JavaScript descriptor. Works for data descriptors and accessor descriptors.

Check if something is a generator function

Returns true if the platform is windows. UMD module, works with node.js, commonjs, browser, AMD, electron, etc.

Returns true if a value has the characteristics of a valid JavaScript data descriptor.

Returns true if a value has the characteristics of a valid JavaScript accessor descriptor.

Check if a value is an object

Returns true if a value exists, false if empty. Works with deeply nested values using object paths.

Detect whether a terminal supports hyperlinks

Type check values

unist utility to recursively walk over nodes, with ancestral information

unist utility to check if a node passes a test

Check if an URL is a valid HTTP URL.

Check which JavaScript environment your code is running in at runtime: browser, Node.js, Bun, etc

Check if your package was installed globally

Runtime library to validate data against TypeScript interfaces

Lint files staged by git

Check if a path is the current working directory

Check if a value is a regular expression

micromark extension to support GFM task list items

Check if your code is running as an npm script

Check that proxies are working, verify their anonymity level, lookup their geographic location by IP address, check for other capabilities such as tunneling and available protocols.

Check whether a request can be retried based on the `error.code`

Isomorphic, functional type-checking for Javascript

mdast extension to parse and serialize GFM task list items

Check if something is a promise

Check if a string matches the name of a Node.js builtin module

Returns `true` if the path appears to be relative.

Returns true if a file path is absolute. Does not rely on the path module and can be used as a polyfill for node.js native `path.isAbolute`.

Check if a file path is a text file

Check if a URL is absolute

Update notifications for your CLI app

Check if a path is in the current working directory

Check if a value is a Fetch network error

Returns `true` if the value is a primitive.

Displays a beginner-friendly message telling your user to upgrade their version of Node

Check if an input value is a ssh url or not.

A little library for asserting types and values, with zero dependencies.

JavaScript Standard Style - ESLint Shareable Config

A simple and composable way to validate data in JavaScript (and TypeScript).

Check if a value is a natural number

Check if a module ID is resolvable with require()

Typescript-compatible minimalistic shallow equality check for arrays/objects

Detect which package manager you're using (yarn or npm)

URI validation functions

this for checking data of ip like region, city dll

Check if a Buffer/Uint8Array is a GZIP file

A straightforward implementation of base58-check encoding

Check if a number is a redirect HTTP status code

Drop-in replacement for `fs.existsSync` with zero dependencies. Other libs I found either have crucial differences from fs.existsSync, or unnecessary dependencies. See README.md for more info.

Get the operating system CPU architecture

Check if a string is a URL

Returns true if a windows file path has invalid characters.

Return true if a value is a valid glob pattern or patterns.

Coalesce for JavaScript. Returns the first value that is not undefined or null.

A type checking library where each exported function returns either true or false and does not throw. Also added tests.

Check if a value is an Observable

Check if a binary is working

Check if a string is SVG

Check if the process is running in a Continuous Integration (CI) environment

Check whether operating system CPU architecture is 64-bit or 32-bit (Supports browsers)

Determine if a filename and/or buffer is text or binary. Smarter detection than the other solutions.

Detect the archive type of a Buffer/Uint8Array

Hook and modify stdout and stderr

hast utility to check if a node has a property

Binary wrapper that makes your programs seamlessly available as local dependencies

Returns true if a file path does not contain any invalid characters.

Detect the archive type of a Buffer/Uint8Array

`util.inspect` with additional type information

Match BCP 47 language tags with language ranges per RFC 4647

Type assertions aka less-broken `typeof`

Validates if a value is an array.

Function argument validation for humans

Check if a binary is working

Check dependencies in your node module

Validates if a value is a number.

Validates if a value is an integer.

Check if a Buffer/Uint8Array is a PNG image

Returns true if the value passed is all whitespace.

A tiny javascript type testing tool

Check if a string only contains alphanumeric characters

Checks if the given value is a window object.

find undeclared identifiers and property accesses in a javascript file.

JavaScript Standard Style JSX support - ESLint Shareable Config

Binary wrapper that makes your programs seamlessly available as local dependencies

Returns `true` if an array has a glob pattern.

Validate an email address according to RFCs 5321, 5322, and others

Check whether a value is "empty".

Update notifications for your CLI app, maintained in CommonJS (CJS)

Check if mobile browser.

Ensure a path doesn't contain null bytes

Check if a Buffer/Uint8Array is a JPEG image

check internet connection speed, IP address, ISP and Ping time

Binary wrapper that makes your programs seamlessly available as local dependencies

Wrap your standards in a tortilla and cover it in special sauce.

Binary wrapper for Flow - A static type checker for JavaScript

Test if a value is an array.

Return a function which tests if every element in an array passes a test condition.

Determine the name of a value's constructor.

Check whether a RegExp flag is supported

JavaScript Standard Style

Check client ip for koa & express.

Test if an object has a specified property.

Check if a Buffer/Uint8Array is a GIF image

A simple and composable way to validate data in JavaScript (and TypeScript).

Test if a value is object-like.

maximally minimal type-testing library

Test if a value is a string.

ESLint shareable config for the Google style

Validate domain name

Check if a string is HTML

Check if an environment is big endian.

Test if a value is a boolean.

Test if a double-precision floating-point numeric value is infinite.

Test if a value is a function.

Test if a value is a Float64Array.

Test if a value is an object.

Test if a value is a Uint32Array.

Check if a URL is relative

Test if a value is a Float32Array.

Try to downgrade the permissions of a process with root privileges and block access if it fails

Test if a value is a number.

ESLint shareable config for XO

Test if a value is a regular expression string.

Determine the specification defined classification of an object.

Test if a value is a regular expression.

Test if a value is a Buffer object.

Test if a value is a plain object.

Determine a value's type.

Test whether a path exists on the filesystem.

Test if a double-precision floating-point numeric value is NaN.

Check if a Buffer/Uint8Array is a TAR file

Test if a value is a Uint8Array.

Test if a value is a Uint16Array.

Check TypeScript type definitions

Detect potential issues with users system that could prevent Yeoman from working correctly

Check if an environment is little endian.

Is this a bluebird promise I see before me?

Check for outdated, incorrect, and unused dependencies.

Get a property from an object using dot (object path) notation.

Check if the current Linux session is using Wayland

check if an AST node is a function of some sort

Check if browser is Firefox

Check if a value is a `Blob`

Check if browser is Internet Explorer

Tiny wrapper around ansi-colors to add colored symbols and a timestamp.

JavaScript/TypeScript linter (ESLint wrapper) with great defaults

Check if Electron is running in development

check if the current node version has async_hooks.

Determine if an array or object is equivalent with another, *not* recursively

Looks up the first non-whitespace character to the left/right of a given index

Utilities to get and check variable types (isString, isPlainObject, isRegExp, etc)

Is given string a language code (as per IANA)

Promisified version of node-which

Check if a process is running

Check if the process is running in an SSH session

ESLint shareable config for TypeScript to be used with eslint-config-xo

Check whether a binary exists in the PATH environment variable

use tcp check domain/ip

Checks TypeScript types match expected values

Check if a value is a function

Checks if the given value is null or undefined

Verify if something is a Promise

Check if a string is a valid JavaScript identifier

3x as fast as `is-whitespace` and `whitespace-regex` thanks to `is-string-blank`. This package is a simple function that accepts an argument and returns `true` if it is a string AND it is not blank. Supports Node and Browser environments.

A gulp plugin for processing files with ESLint

Check whether a package or organization name is available on npm

Reshape into a better npm audit for the community and encourage more people to include security audit into their process.

Checks if the given value is a native function.

A JSON fixer

Check if a Buffer/Uint8Array is a ZIP file

Returns true if the given is falsey (according to JavaScript) or matches a 'falsey' keyword.

Ember CLI addon for detecting missing npm and bower dependencies before executing ember commands

Parse dotenv files for Boolean, Array, and Number variable types, built for CrocodileJS

check if an AST node is a MemberExpression, in general or a specific one

Keep watch of your bundle size

JavaScript Standard Style React/JSX support - ESLint Shareable Config

Detect the audio type of a Buffer/Uint8Array

Context menu for your Electron app

Detect the image type of an ArrayBuffer/Uint8Array

Checks if a given object is iterable

Check if the machine is running Windows or not.

A TypeScript ESLint config that loves you

Test if a finite numeric value is an odd number.

checks the all of the hyperlinks in a markdown text to determine if they are alive or dead

checks whether a hyperlink is alive (200 OK) or dead

A proxy to `path`, replacing `\` with `/` for all results

Check if a Buffer/Uint8Array is a BZIP2 file

Check if a directory is empty.

Check if a Node.js Buffer or Uint8Array is UTF-8

Utils to deal with TCP ports and hostnames. Safe for everyday use.

ESLint shareable config for React to be used with eslint-config-xo

JavaScript Semistandard Style - ESLint Shareable Config

ESLint shareable config for XO with 2-space indent

Check if a value is undefined or not.

Keep your library size in check

Detect the appearance of an element in the browser DOM

Validates password according to flexible and intuitive specifications

Check if a string is a valid filename

allows easy type enforcement for all JS types objects and classes. it is also extensible and provides simple to use type checks for your own custom classes and types

Test if a finite double-precision floating-point number is an integer.

Test if a double-precision floating-point numeric value is positive zero.

Checks for URLs during typing and pasting and automatically converts them to links.

Check the validity of the format of an EU VAT number

Test if a finite numeric value is an even number.

A collection of functions for working with different casings.

Aids humans and automation in managing npm audit results

Check if an object is an array or a typed array

Check if a string is a valid IP address

Returns true if an object has an own, nested property using dot notation paths ('a.b.c').

Test if a double-precision floating-point numeric value is negative zero.

Checks that given package is installed globally or locally.

A command line utility to read version from package.json and attach it into your module as a property

Base58Check encoding

Validate hostname based on RFC-1123

TypeScript / JavaScript library for detect WebAssembly features in node.js & browser

Assert a given object is a valid glob option

is-iojs determines if runtime is io.js.

Async npm module for Node JS that reads the first line of a file

Returns `true` if a value exists in the given string, array or object.

Test if a value is a number having an integer value.

Test if a value is NaN.

TypeScript Standard Style based on StandardJS

Test if a value is a number having a nonnegative integer value.