JSPM

Test if a value is a Uint8Array.

Test if a value is a Uint16Array.

Test if a value is a regular expression.

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

JavaScript/TypeScript linter (ESLint wrapper) with great defaults

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

Check for outdated, incorrect, and unused dependencies.

Check if an environment is little endian.

check if an AST node is a function of some sort

Test if a value is a Buffer object.

Test if a value is a plain object.

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

Test whether a path exists on the filesystem.

Check TypeScript type definitions

Check if a Buffer/Uint8Array is a TAR file

Is this a bluebird promise I see before me?

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

Check if browser is Firefox

Check if a value is a `Blob`

Check if a process is running

Check if browser is Internet Explorer

Check whether a binary exists in the PATH environment variable

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

Promisified version of node-which

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

Verify if something is a Promise

Is given string a language code (as per IANA)

Check if Electron is running in development

check if the current node version has async_hooks.

Detect the audio type of a Buffer/Uint8Array

Checks if the given value is null or undefined

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

Checks if a given object is iterable

Checks TypeScript types match expected values

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.

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

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

Check if a string is a valid JavaScript identifier

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

Check whether a package or organization name is available on npm

Check if a string is an IP address

A gulp plugin for processing files with ESLint

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.

JavaScript Standard Style React/JSX support - ESLint Shareable Config

Keep watch of your bundle size

Check if a Buffer/Uint8Array is a ZIP file

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

A JSON fixer

Check if a directory is empty.

A TypeScript ESLint config that loves you

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

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

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

Detect the image type of an ArrayBuffer/Uint8Array

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

Check if a value is a function

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

JavaScript Semistandard Style - ESLint Shareable Config

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

Validates password according to flexible and intuitive specifications

ESLint shareable config for XO with 2-space indent

Check if a Buffer/Uint8Array is a BZIP2 file

Check if a string is a valid filename

Test if a finite numeric value is an odd number.

is-iojs determines if runtime is io.js.

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

Keep your library size in check

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

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

Check the validity of the format of an EU VAT number

Aids humans and automation in managing npm audit results

Check if an object is an array or a typed array

Context menu for your Electron app

A collection of functions for working with different casings.

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

Validate hostname based on RFC-1123

Check whether a binary version satisfies a semver range

Check if the machine is running Windows or not.

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

Test if a value is NaN.

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

Hunspell compatible spell checker

TypeScript Standard Style based on StandardJS

Check if the package is being installed by another package

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

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

Test if a finite numeric value is an even number.

Check if the process is running as administrator on Windows

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

Test if a value is an Int32Array.

Detect the appearance of an element in the browser DOM

Markdown TaskList components

Test if an object's own property is enumerable.

Test if a value is a Uint8ClampedArray.

Test if a value is an Int16Array.

Assert a given object is a valid glob option

Check if a value is undefined or not.

$(document).ready() for the 21st century

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

Checks that given package is installed globally or locally.

All the goodness of `feross/standard` with semicolons sprinkled on top.

A pure css library to beautify checkbox and radio buttons.

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

code > prettier > stylelint > formatted code

Returns true if the current node version matches the given semver expression

Check if the user is running the latest version of the app

Check if the process is running with elevated privileges

Test if a value is an Int8Array.

Test if a value is a collection.

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

Test if a value is an arguments object.

Validate glob options

ESlint plugin to define custom module dependency rules.

Get or set a deep value using a keypath string. Supports bracket and dot notation

Create an error from the result of validate-glob-opts

Check if a file path is an image

A tool to enable the checking, inserting and removal of licenses

Fully customizable animated bouncy checkbox for React Native

Test if a value is an Error object.

Checks if an input string is a capitalized or not.

Standard assertion utilities.

Skema provides a handy & composable way to validate / transform / purify the input data.

Base58Check encoding

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 whether a value has in its prototype chain a specified constructor as a prototype property.

Minimal JavaScript type checking library

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

check if an AST node is a call to require()

Run your TypeScript type tests using Jest

A gulp plugin to lint code with ESLint 8 and 9.

Compile TypeScript interfaces into a description that allows runtime validation

Get or check the current macOS version

Test if a value is an ArrayBuffer.

Test if a value is a complex number-like object.

Set of various predicates for type checking, assertions, filtering etc

Checks if the given value is an array or array-like object.

Test if a value is a number having a positive value.

check if an AST node is a call to require()

Easily expose your http server's health.

Test if a value is an array-like object.

Check if something is a positive number

Determines whether a string ends with the characters of another string.

Test if a value is array-like.

Assertions and Validations for TypeScript

Shallow equal check object.

Lint CSS for email support against caniemail database.

Run elm-review from Node.js

Test if a value is a Complex64Array.

Check if something is a Node.js stream. This is a fork of sindresorhus/is-stream, but with CommonJS support.

Check if a String/Buffer is TTF

Type check values: `is.string('🦄') //=> true`

Upcast is a low-level JavaScript type checking and casting library

Check if a number is in a given range

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Check whether a file can be executed

Check if a file path is a video file

Noir ESLint shareable config

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

Check types

Check that all files match prettier code style.

Check if a file is a directory

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

Test if a value is a typed array.

Test if a value is a complex typed array.

ESLint sharable config for strict linting

Check if a JavaScript environment has a DOM

Test if a value is a Complex128Array.

Check if an Array is sorted

Utilities for formatting and linting a Dockerfile.

Test if an array-like object supports the accessor (get/set) protocol.

Type checking for .eslintrc.json

A light-weight jQuery "dirty forms" Plugin - it monitors HTML forms and alerts users to unsaved changes if they attempt to close the browser or navigate away from the page. (Are you sure?)

Test if a value is an array-like object of numbers.

Test whether a module is available as a dependency

Check if NPM package names conflict

Check if a String/Buffer/ArrayBuffer is OTF

Returns true if an array has duplicate elements or a string has duplicate characters.

Checkbox component for react native, it works on iOS and Android.

Utility to check if internet is connected or not

Validates if a value is a JavaScript object.

Tiny, streaming, seedable CRC32 library, compatible with the crypto.Hash API

Test if a value is typed-array-like.

Returns true if a value is the global or window object.

Determine if a variable or expression is a React element or component

Check the validity of the format of an EU VAT number

Library to check variable type and properties in object.

Convert Ethereum address to a checksummed address

Build a navigation structure programatically

Check that given value is valid hex color, using `hex-color-regex` - the best regex for matching hex color values

If X, return Y, else throw Z.

Delete files and folders and any intermediate directories if they exist (sync and async).

Check if something is a negative number

Build templates for initial values

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

[![github actions][actions-image]][actions-url] [![coverage][codecov-image]][codecov-url] [![dependency status][deps-svg]][deps-url] [![dev dependency status][dev-deps-svg]][dev-deps-url] [![License][license-image]][license-url] [![Downloads][downloads-im

Check if a string can be used as a JavaScript variable name

Validate the name of a custom element

Validates if a value is undefined.

check if urls are dead or alive

Check if an email domain belongs to an educational instutition

Tiny module for checking if Promise is globally available

Check to see if a token is expired using only the token itself without a secret key or validation

A simple function for interrupting program flow if a condition isn’t met.

Test if an array-like value contains a search value.

Check if an object is empty or not.

Check if an environment is little endian.

Checks the integrity of an Endo bundle.

Check your Vue project for unused Components

Run commands if on specified node version.

Test if a value is a probability.

The hasNestedProperty method missing in Object. This module does not extend Object.

Verifies email domains

🔌 CLI to check/generate .env files and maintain them synchronized

Check if a Buffer/Uint8Array is WOFF

Robustly checks an array of URLs for liveness.

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

Check if a string or buffer ends with a given string

Create JSON Schema validator from TypeScript.

Keep your package.json version requirements satisfied

Check if a Buffer/Uint8Array is EOT

Check if a Buffer/Uint8Array is a FLAC file.

Check a character if it is a correctly supported emoji.

Test if a double-precision floating-point number is a probability.

Checks if the given value is a valid array-like index.

Check if node_modules match package.json versions. npm / yarn install shortcut.

Check if a buffer/Uint8Array is a woff2 file

Check if two numbers are equal within a given tolerance

Utility for linting a docker file against accepted good practices

Simple, lightweight at-runtime type checking functions, with full TypeScript support

Check if an URL is a valid HTTP URL.

Returns `true` if text is upper case only.

Check if a file exists without try catch

Check whether a string is a valid HTTP URL

Check for outdated, incorrect, and unused dependencies.

Verifies that typescript examples in markdown files actually compile.

## Overview

Check if a Buffer/Uint8Array is a m4a file.

Check if a Buffer/Uint8Array is a wav file.

Test if a value is an array-like object containing only nonnegative integers.

Test if a value is an array of strings.

check RegExp ( regular expressions ) support

Returns `true` if text is lower case only

Detect file type by signature

regexp-helper

Check if a Buffer/Uint8Array is a MP3 file.

regexp-helper-core

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

Type check values. This is a fork of sindresorhus/is, but with CommonJS support.