JSPM

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

Check if a Buffer/Uint8Array is a ZIP file

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

Keep watch of your bundle size

Check whether a package or organization name is available on npm

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

A JSON fixer

JavaScript Standard Style React/JSX support - ESLint Shareable Config

Check if a value is a function

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

Check if a directory is empty.

A TypeScript ESLint config that loves you

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

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

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

Detect the image type of an ArrayBuffer/Uint8Array

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

ESLint shareable config for XO with 2-space indent

JavaScript Semistandard Style - ESLint Shareable Config

Validates password according to flexible and intuitive specifications

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.

Aids humans and automation in managing npm audit results

Keep your library size in check

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

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

is-iojs determines if runtime is io.js.

Context menu for your Electron app

A collection of functions for working with different casings.

Check the validity of the format of an EU VAT number

Check if an object is an array or a typed array

Validate hostname based on RFC-1123

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

Check if the machine is running Windows or not.

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

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

Test if a value is NaN.

Check whether a binary version satisfies a semver range

Hunspell compatible spell checker

Markdown TaskList components

TypeScript Standard Style based on StandardJS

Check if the package is being installed by another package

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

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

Test if an object's own property is enumerable.

Check if the process is running as administrator on Windows

Test if a value is an Int32Array.

Check if a value is undefined or not.

Test if a finite numeric value is an even number.

Test if a value is a Uint8ClampedArray.

Test if a value is an Int16Array.

Assert a given object is a valid glob option

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

Detect the appearance of an element in the browser DOM

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

Checks that given package is installed globally or locally.

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

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

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

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

A pure css library to beautify checkbox and radio buttons.

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

code > prettier > stylelint > formatted code

Test if a value is a collection.

Check if the process is running with elevated privileges

Test if a value is an Int8Array.

Test if a value is an arguments object.

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

Check if a file path is an image

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

ESlint plugin to define custom module dependency rules.

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

Validate glob options

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

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

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

Test if a value is an Error object.

Fully customizable animated bouncy checkbox for React Native

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

Standard assertion utilities.

Checks if an input string is a capitalized or not.

Base58Check encoding

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

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

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

Get or check the current macOS version

Test if a value is an ArrayBuffer.

Run your TypeScript type tests using Jest

Minimal JavaScript type checking library

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

Compile TypeScript interfaces into a description that allows runtime validation

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

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

Assertions and Validations for TypeScript

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

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

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

Run elm-review from Node.js

Easily expose your http server's health.

Test if a value is an array-like object.

Check if something is a positive number

Test if a value is array-like.

Shallow equal check object.

Lint CSS for email support against caniemail database.

Test if a value is a Complex64Array.

Check if a String/Buffer is TTF

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

Check whether a file can be executed

Check if a file path is a video file

Check if a number is in a given range

Check if a file is a directory

[![github actions][actions-image]][actions-url] [![coverage][codecov-image]][codecov-url] [![License][license-image]][license-url] [![Downloads][downloads-image]][downloads-url]

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

Check types

Utilities for formatting and linting a Dockerfile.

Check that all files match prettier code style.

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

ESLint sharable config for strict linting

Test if a value is a typed array.

Test if a value is a complex typed array.

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

Check if a JavaScript environment has a DOM

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

Check if an Array is sorted

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

Type checking for .eslintrc.json

Test whether a module is available as a dependency

Test if a value is a Complex128Array.

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

Validates if a value is a JavaScript object.

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?)

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

Convert Ethereum address to a checksummed address

Check if a String/Buffer/ArrayBuffer is OTF

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

Test if a value is typed-array-like.

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

Build templates for initial values

Check the validity of the format of an EU VAT number

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

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

Library to check variable type and properties in object.

Utility to check if internet is connected or not

Check if NPM package names conflict

If X, return Y, else throw Z.

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

Build a navigation structure programatically

Check if something is a negative number

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

Validate the name of a custom element

[![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

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

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

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

Validates if a value is undefined.

Check if an email domain belongs to an educational instutition

check if urls are dead or alive

Checks the integrity of an Endo bundle.

Tiny module for checking if Promise is globally available

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

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

Check if an environment is little endian.

Run commands if on specified node version.

Check if an object is empty or not.

Check your Vue project for unused Components

Test if a value is a probability.

Verifies email domains

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

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

Check if a Buffer/Uint8Array is EOT

Robustly checks an array of URLs for liveness.

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

Check if a string or buffer ends with a given string

Check if a Buffer/Uint8Array is WOFF

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

Create JSON Schema validator from TypeScript.

Check if a Buffer/Uint8Array is a FLAC file.

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

Check if a buffer/Uint8Array is a woff2 file

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

Check a character if it is a correctly supported emoji.

Check if a file exists without try catch

Verifies that typescript examples in markdown files actually compile.

Check if two numbers are equal within a given tolerance

Utility for linting a docker file against accepted good practices

Noir ESLint shareable config

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

Check if an URL is a valid HTTP URL.

Check for outdated, incorrect, and unused dependencies.

Check if a Buffer/Uint8Array is a MP3 file.

Check whether a string is a valid HTTP URL

Returns `true` if text is upper case only.

## Overview

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

Returns `true` if text is lower case only

Check if a Buffer/Uint8Array is a m4a file.

Check if a Buffer/Uint8Array is a wav file.

Detect file type by signature

Test if a value is an array of strings.

check RegExp ( regular expressions ) support

Checks if a newer version is available for command line interfaces

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.

regexp-helper

regexp-helper-core

Test if a value is Node stream-like.

Check if a Buffer/Uint8Array is an OGG file.

ESLint shareable config for the HTML Academy style

Test if a value is Node writable stream-like.

Second generation object or request validator for node.js

Test if something is an object literal

Report tests failures from Jest in GitHub

JavaScript Standard Style JSDoc support - ESLint Shareable Config

Check if an Iterable is empty

Check to see if a directory exists

Detect when an element is ready in the DOM

Check if a URL exists.

Test if a value is an array of probabilities that sum to one.

React components for [Stripe.js and Elements](https://stripe.com/docs/stripe-js).

[![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

Test if a value is a DataView.

Check the licenses for the packages that you are using

check json object matches template

Checks if package-lock.json is Up To Date (= UTD)

Detect if DevTools is open and its orientation

Keep your package.json version requirements satisfied

An ESLint Shareable Config for video.js Standard Style.

Test if a value is null.

Stylelint shareable config for XO

Unit tests for .d.ts TypeScript definitions

Add support to do 'Spell checking', with a toggle on/off option in Settings

Validates if a value is a boolean.

Validates if a value is a string.

Validates if a value is NaN.

Fast link checker, wrapped from filiph/linkcheck

A small and simple utility package that can validate any kind of image. It can detect corrupt files, or invalid image urls

Check that email addresses are really able to accept emails by pinging the DNS and checking for active MX records.

A straightforward implementation of base58-check encoding

Validates if a value is a URI.

Generate JavaScript-compatible regular expressions with chinese/jp/zh/cn

Validates if a value is a NaN primitive.

ESLint config for Melinda's backend applications

The Hunspell binding for nodejs that exposes as much of hunspell as possible and also adds new features. Hunspell is a first class spellcheck library used by Google, Apple, and Mozilla.

A simple and fully customizable React checkbox input component.

Test if an input value is an ndarray order.