JSPM

Typescript-compatible minimalistic shallow equality check for arrays/objects

Extremely fast function optimized for deep equality checks of json-serializable plain objects.

Test for deep equality between two values.

Deep runtime type equality testing

Minimalistic shallow equality check for arrays/objects

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

Shallow check two arrays for loose equality

Check if argv has a specific flag

Check if something is a Node.js stream

Get the native type of a value.

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

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

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

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

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

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

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

Check if a file path is a binary file

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

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

Detect whether the terminal supports Unicode

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

Check if something is a generator function

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

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

Check if a value is an object

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

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

Type check values

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

Detect whether a terminal supports hyperlinks

unist utility to check if a node passes a test

unist utility to recursively walk over nodes, with ancestral information

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 your code is running as an npm script

micromark extension to support GFM task list items

Check if a value is a regular expression

Isomorphic, functional type-checking for Javascript

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

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

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

mdast extension to parse and serialize GFM task list items

Check if something is a promise

Update notifications for your CLI app

Check if a URL is absolute

Check if a file path is a text file

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 path is in the current working directory

Check if a value is a Fetch network error

Shallow equal check object.

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

Check if a value is a natural number

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

JavaScript Standard Style - ESLint Shareable Config

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

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

Returns `true` if the value is a primitive.

Check if a Buffer/Uint8Array is a GZIP file

A straightforward implementation of base58-check encoding

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

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

Check if a number is a redirect HTTP status code

Returns true if a windows file path has invalid characters.

Check if a module ID is resolvable with require()

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

URI validation functions

Check if a string is a URL

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.

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

Get the operating system CPU architecture

Detect the archive type of a Buffer/Uint8Array

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

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

Check if a binary is working

Hook and modify stdout and stderr

Check if a local or remote port is reachable

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

Binary wrapper that makes your programs seamlessly available as local dependencies

Check if a value is an Observable

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

hast utility to check if a node has a property

Check if a string is SVG

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

Type assertions aka less-broken `typeof`

`util.inspect` with additional type information

Detect the archive type of a Buffer/Uint8Array

Check if a binary is working

A HOC enabling you to easily implement extended property equality checks for your React Components

Validates if a value is an array.

Check if a string is an IP address

Match BCP 47 language tags with language ranges per RFC 4647

Check dependencies in your node module

A tiny javascript type testing tool

Validates if a value is a number.

Binary wrapper that makes your programs seamlessly available as local dependencies

Returns true if the value passed is all whitespace.

Function argument validation for humans

Checks if the given value is a window object.

Validates if a value is an integer.

JavaScript Standard Style JSX support - ESLint Shareable Config

Check if a Buffer/Uint8Array is a PNG image

find undeclared identifiers and property accesses in a javascript file.

Check if a string only contains alphanumeric characters

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

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

Check whether a value is "empty".

Binary wrapper that makes your programs seamlessly available as local dependencies

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

Provides a collection of runtime assertion tools for checking strict equality, type, and range of a set of values.

Check if mobile browser.

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

Check if a Buffer/Uint8Array is a JPEG image

Binary wrapper for Flow - A static type checker for JavaScript

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

Determine the name of a value's constructor.

Test if an object has a specified property.

Test if a value is an array.

Check whether a RegExp flag is supported

Test if a value is object-like.

Ensure a path doesn't contain null bytes

Check if a Buffer/Uint8Array is a GIF image

JavaScript Standard Style

Check if an environment is big endian.

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

maximally minimal type-testing library

Check if a string is HTML

Test if a value is a regular expression string.

Validate domain name

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

ESLint shareable config for XO

Test if a value is a string.

Test if a value is a boolean.

Test if a value is a function.

ESLint shareable config for the Google style

Test if a value is an object.

Test if a value is a Float32Array.

Test if a value is a number.

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

Test if a value is a Float64Array.

Test if a value is a Uint32Array.

Check if a URL is relative

Test if a value is a Buffer object.

JavaScript/TypeScript linter (ESLint wrapper) with great defaults

Test if a value is a plain object.

Test whether a path exists on the filesystem.

Determine the specification defined classification of an object.

Check if a process is running

Test if a value is a regular expression.

Determine a value's type.

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

check if an AST node is a function of some sort

Check for outdated, incorrect, and unused dependencies.

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

Test if a value is a Uint8Array.

Test if a value is a Uint16Array.

Check if a Buffer/Uint8Array is a TAR file

Check if an environment is little endian.

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

Is this a bluebird promise I see before me?

Check TypeScript type definitions

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

Check if a value is a `Blob`

Check if browser is Firefox

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)

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

Promisified version of node-which

Check if Electron is running in development

check if the current node version has async_hooks.

Is given string a language code (as per IANA)

Check if two values are shallowly equal to each other.

Verify if something is a Promise

Checks if the given value is null or undefined

Checks TypeScript types match expected values

Checks if a given object is iterable

Detect the audio type of a Buffer/Uint8Array

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

Check if a string is an IP address

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

Check if a string is a valid JavaScript identifier

Checks if the given value is a native function.

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

A gulp plugin for processing files with ESLint

Check whether a package or organization name is available on npm

Keep watch of your bundle size

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.

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

Check if a Buffer/Uint8Array is a ZIP file

Check if a value is a function

A TypeScript ESLint config that loves you

JavaScript Standard Style React/JSX support - ESLint Shareable Config

Check if a directory is empty.

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

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

A JSON fixer

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

Detect the image type of an ArrayBuffer/Uint8Array

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

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

ESLint shareable config for XO with 2-space indent

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

Check if a Buffer/Uint8Array is a BZIP2 file

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

Test if a finite numeric value is an odd number.

Check if a string is a valid filename

Keep your library size in check

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Context menu for your Electron app

Check the validity of the format of an EU VAT number

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

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 if an object is an array or a typed array

A collection of functions for working with different casings.

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

Check if the machine is running Windows or not.

Validate hostname based on RFC-1123

Aids humans and automation in managing npm audit results

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 positive zero.

TypeScript Standard Style based on StandardJS

is-iojs determines if runtime is io.js.

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

Test if a value is NaN.

Detect the appearance of an element in the browser DOM

Hunspell compatible spell checker

Check if the package is being installed by another package

Check whether a binary version satisfies a semver range

Check if the process is running as administrator on Windows

Check if a value is undefined or not.

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

Base58Check encoding

Test if a finite numeric value is an even number.

Test if an object's own property is enumerable.

Test if a value is a Uint8ClampedArray.

Test if a value is an Int16Array.

Test if a value is an Int32Array.

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

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

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

Checks that given package is installed globally or locally.