JSPM

Typescript-compatible minimalistic shallow equality check for arrays/objects

Test for deep equality between two values.

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

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

Shallow check two arrays for strict equality

Check if argv has a specific flag

Get the native type of a value.

Check if something is a Node.js stream

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

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

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

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

Returns true if a string has an extglob.

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.

Check if a value is a plain object

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

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 a value is a plain object, array or function.

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

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

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

Detect whether the terminal supports Unicode

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.

Type check values

Detect whether a terminal supports hyperlinks

unist utility to recursively walk over nodes, with ancestral information

unist utility to check if a node passes a test

Check if your package was installed globally

Check if a path is the current working directory

Runtime library to validate data against TypeScript interfaces

Lint files staged by git

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

Check if your code is running as an npm script

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

Check if something is a promise

Check if a value is a regular expression

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

Isomorphic, functional type-checking for Javascript

Check if a URL is absolute

Check if a path is in the current working directory

Check if a file path is a text file

Update notifications for your CLI app

micromark extension to support GFM task list items

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

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`.

mdast extension to parse and serialize GFM task list items

JavaScript Standard Style - ESLint Shareable Config

Check if a value is a Fetch network error

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

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.

Shallow equal check object.

Check if a module ID is resolvable with require()

Returns `true` if the value is a primitive.

Check if a value is a natural number

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

Check if a number is a redirect HTTP status code

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

A straightforward implementation of base58-check encoding

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

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

Check if a value is an Observable

Check if a Buffer/Uint8Array is a GZIP file

URI validation functions

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.

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

Check if a string is SVG

Returns true if a windows file path has invalid characters.

Hook and modify stdout and stderr

Check if a local or remote port is reachable

Detect the archive type of a Buffer/Uint8Array

Check if a string is a URL

Lightweight and simple Javascript tool to compare equality with objects, arrays and other Javascript object types.

Get the operating system CPU architecture

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

Type assertions aka less-broken `typeof`

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

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

JavaScript Standard Style JSX support - ESLint Shareable Config

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

Check if a binary is working

hast utility to check if a node has a property

Check if a string is an IP address

Binary wrapper that makes your programs seamlessly available as local dependencies

Check if a binary is working

Checks if the given value is a window object.

Detect the archive type of a Buffer/Uint8Array

Check if a string only contains alphanumeric characters

`util.inspect` with additional type information

Validates if a value is an array.

Returns true if the value passed is all whitespace.

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

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

Validates if a value is a number.

Function argument validation for humans

A tiny javascript type testing tool

Check dependencies in your node module

find undeclared identifiers and property accesses in a javascript file.

Ensure a path doesn't contain null bytes

Match BCP 47 language tags with language ranges per RFC 4647

Binary wrapper that makes your programs seamlessly available as local dependencies

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

Check if a Buffer/Uint8Array is a PNG image

Validates if a value is an integer.

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

JavaScript Standard Style

Check whether a value is "empty".

Binary wrapper for Flow - A static type checker for JavaScript

Check if a Buffer/Uint8Array is a JPEG image

Binary wrapper that makes your programs seamlessly available as local dependencies

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

ESLint shareable config for the Google style

Check whether a RegExp flag is supported

Test if an object has a specified property.

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.

maximally minimal type-testing library

Check if a Buffer/Uint8Array is a GIF image

Validate domain name

Check TypeScript type definitions

Test if a value is object-like.

Check for outdated, incorrect, and unused dependencies.

Test if a value is a string.

Test if a value is a boolean.

Test if a value is a function.

Check if a URL is relative

Check if an environment is big endian.

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

Test if a value is a regular expression.

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

ESLint shareable config for XO

Test if a value is a Float64Array.

Check if a string is HTML

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

Test if a value is a Uint32Array.

Check if mobile browser.

Test if a value is a regular expression string.

check if an AST node is a function of some sort

Test if a value is an object.

Test if a value is a Float32Array.

Test if a value is a number.

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

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

Test if a value is a Buffer object.

Test whether a path exists on the filesystem.

Is this a bluebird promise I see before me?

Test if a value is a plain object.

Detect the audio type of a Buffer/Uint8Array

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

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

Determine the specification defined classification of an object.

Check if a Buffer/Uint8Array is a TAR file

Determine a value's type.

Check if a value is a `Blob`

Test if a value is a Uint8Array.

Test if a value is a Uint16Array.

Check if an environment is little endian.

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

Promisified version of node-which

JavaScript/TypeScript linter (ESLint wrapper) with great defaults

Check if browser is Internet Explorer

Is given string a language code (as per IANA)

Check if a process is running

Check if browser is Firefox

Check whether a binary exists in the PATH environment variable

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

Check whether a package or organization name is available on npm

Check if two values are shallowly equal to each other.

Check if a value is a function

Checks TypeScript types match expected values

check if the current node version has async_hooks.

Check if Electron is running in development

A JSON fixer

A gulp plugin for processing files with ESLint

Verify if something is a Promise

Checks if a given object is iterable

Checks if the given value is null or undefined

Check if a Buffer/Uint8Array is a ZIP file

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

JavaScript Standard Style React/JSX support - ESLint Shareable Config

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

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

Checks if the given value is a native function.

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

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

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

Check if a string is an IP address

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

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.

Check if a string is a valid JavaScript identifier

JavaScript Semistandard Style - ESLint Shareable Config

Check if a directory is empty.

Markdown TaskList components

Detect the image type of an ArrayBuffer/Uint8Array

Check if a Buffer/Uint8Array is a BZIP2 file

ESLint shareable config for XO with 2-space indent

A TypeScript ESLint config that loves you

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

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

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

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

is-iojs determines if runtime is io.js.

Test if a finite numeric value is an odd number.

Validates password according to flexible and intuitive specifications

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

Keep your library size in check

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

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.

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

TypeScript Standard Style based on StandardJS

Aids humans and automation in managing npm audit results

Check if a string is a valid filename

Test if a value is NaN.

Context menu for your Electron app

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

Validate hostname based on RFC-1123

Check the validity of the format of an EU VAT number

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

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

Check if the machine is running Windows or not.

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

Test if a finite numeric value is an even number.

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

A collection of functions for working with different casings.

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

Check if the package is being installed by another package

Checks that given package is installed globally or locally.

Check if an object is an array or a typed array

Check whether a binary version satisfies a semver range

Hunspell compatible spell checker

Check if a value is undefined or not.

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

Assert a given object is a valid glob option

Noir ESLint shareable config

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