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

Check if argv has a specific flag

Get the native type of a value.

Check if something is a Node.js stream

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

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

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

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

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 a file path is a binary file

Check if a value is a plain object

Returns true if a string has an extglob.

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

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

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

Check if something is a generator function

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

Detect whether the terminal supports Unicode

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 descriptor. Works for data descriptors and accessor descriptors.

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

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

Runtime library to validate data against TypeScript interfaces

Check if a path is the current working directory

Check if your code is running as an npm script

Lint files staged by git

Check if a value is a regular expression

Shallow check two arrays for loose equality

micromark extension to support GFM task list items

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

Check if something is a promise

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 path is in the current working directory

Check if a URL is absolute

Check if a file path is a text file

Update notifications for your CLI app

mdast extension to parse and serialize GFM task list items

Check if a value is a Fetch network error

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

Shallow equal check object.

JavaScript Standard Style - ESLint Shareable Config

Returns `true` if the value is a primitive.

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

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

Check if a value is a natural number

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

Check if a Buffer/Uint8Array is a GZIP file

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 module ID is resolvable with require()

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

URI validation functions

A straightforward implementation of base58-check encoding

Check if a number is a redirect HTTP status code

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.

Get the operating system CPU architecture

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.

Check if a value is an Observable

Check if a binary is working

Detect the archive type of a Buffer/Uint8Array

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

Check if a local or remote port is reachable

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.

Binary wrapper that makes your programs seamlessly available as local dependencies

Check if a string is SVG

Type assertions aka less-broken `typeof`

Hook and modify stdout and stderr

hast utility to check if a node has a property

Detect the archive type of a Buffer/Uint8Array

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

`util.inspect` with additional type information

Validates if a value is an array.

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

Check if a binary is working

Match BCP 47 language tags with language ranges per RFC 4647

Check dependencies in your node module

Check if a string is an IP address

Validates if a value is a number.

Function argument validation for humans

A tiny javascript type testing tool

JavaScript Standard Style JSX support - ESLint Shareable Config

Checks if the given value is a window object.

Validates if a value is an integer.

Check if a Buffer/Uint8Array is a PNG image

Binary wrapper that makes your programs seamlessly available as local dependencies

Returns true if the value passed is all whitespace.

Check if a string only contains alphanumeric characters

find undeclared identifiers and property accesses in a javascript file.

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

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

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

Binary wrapper that makes your programs seamlessly available as local dependencies

Check whether a value is "empty".

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

Check if a Buffer/Uint8Array is a JPEG image

Check if mobile browser.

Ensure a path doesn't contain null bytes

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.

JavaScript Standard Style

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

Test if an object has a specified property.

Validate domain name

Check if a Buffer/Uint8Array is a GIF image

Test if a value is object-like.

Check whether a RegExp flag is supported

Check if an environment is big endian.

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

Check if a string is HTML

ESLint shareable config for the Google style

Check if a URL is relative

ESLint shareable config for XO

Test if a value is a regular expression string.

Test if a value is a string.

Test if a value is a boolean.

Test if a value is a function.

Test if a value is a Float64Array.

Test if a value is a Uint32Array.

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

maximally minimal type-testing library

Check for outdated, incorrect, and unused dependencies.

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

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

Test if a value is an object.

Test if a value is a Float32Array.

Test if a value is a number.

Determine the specification defined classification of an object.

Test if a value is a regular expression.

Check TypeScript type definitions

Determine a value's type.

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

JavaScript/TypeScript linter (ESLint wrapper) with great defaults

Test if a value is a Uint8Array.

Test if a value is a Uint16Array.

Check if an environment is little endian.

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

Test if a value is a Buffer object.

check if an AST node is a function of some sort

Test if a value is a plain object.

Check if a Buffer/Uint8Array is a TAR file

Test whether a path exists on the filesystem.

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

Is this a bluebird promise I see before me?

Check if browser is Firefox

Check if a value is a `Blob`

Check if browser is Internet Explorer

Check if a process is running

Promisified version of node-which

Check whether a binary exists in the PATH environment variable

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

Check if two values are shallowly equal to each other.

Verify if something is a Promise

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

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.

Checks if a given object is iterable

Detect the audio type of a Buffer/Uint8Array

Checks if the given value is null or undefined

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.

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.

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

Checks if the given value is a native function.

Check if a string is a valid JavaScript identifier

Check if a string is an IP address

Keep watch of your bundle size

A gulp plugin for processing files with ESLint

JavaScript Standard Style React/JSX support - ESLint Shareable Config

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 Buffer/Uint8Array is a ZIP file

A JSON fixer

Check if a directory is empty.

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

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

A TypeScript ESLint config that loves you

Detect the image type of an ArrayBuffer/Uint8Array

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

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

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

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

JavaScript Semistandard Style - ESLint Shareable Config

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.

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is-iojs determines if runtime is io.js.

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

Keep your library size in check

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

Aids humans and automation in managing npm audit results

Check the validity of the format of an EU VAT number

A collection of functions for working with different casings.

Context menu for your Electron app

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

Check if an object is an array or a typed array

Check if the machine is running Windows or not.

Validate hostname based on RFC-1123

Check whether a binary version satisfies a semver range

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

Test if a value is NaN.

TypeScript Standard Style based on StandardJS

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

Hunspell compatible spell checker

Check if the package is being installed by another package

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

Markdown TaskList components

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

Test if a finite numeric value is an even number.

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

Test if an object's own property is enumerable.

Detect the appearance of an element in the browser DOM

Check if the process is running as administrator on Windows

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

Assert a given object is a valid glob option

Test if a value is an Int32Array.

Test if a value is a Uint8ClampedArray.

Test if a value is an Int16Array.

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

Check if a value is undefined or not.