JSPM

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

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

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

Check if a file path is a binary file

Check if a file path is a text file

Type check values

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

Check if a value is a plain object

Check if a value is an Observable

Check if a value is an object

Check if something is a generator function

Detect the archive type of a Buffer/Uint8Array

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

Runtime library to validate data against TypeScript interfaces

Check if something is a Node.js stream

Check if a Buffer/Uint8Array is a GIF image

Get the native type of a value.

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

Check if a Buffer/Uint8Array is a PNG image

Check if argv has a specific flag

Check if a Buffer/Uint8Array is a JPEG image

Returns true if a windows file path has invalid characters.

Check if something is a promise

Check if a value is a regular expression

Check if a value is a `Blob`

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 the character represented by a given Unicode code point is fullwidth

Check if a Buffer/Uint8Array is a GZIP file

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

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

Check if a string is SVG

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

Validates if a value is an array.

Check if a file path is an image

JavaScript Standard Style - ESLint Shareable Config

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

Validates if a value is a number.

Validates if a value is an integer.

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

Type assertions aka less-broken `typeof`

Check if a URL is absolute

Check if a local or remote port is reachable

Check if a value is a Fetch network error

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

Check if a path is the current working directory

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

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

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

Detect the archive type of a Buffer/Uint8Array

unist utility to check if a node passes a test

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

Returns `true` if the value is a primitive.

Returns true if a string has an extglob.

Check if a module ID is resolvable with require()

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

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

Lint files staged by git

Detect the image type of an ArrayBuffer/Uint8Array

Check if a Buffer/Uint8Array is a TAR file

Check if a path is in the current working directory

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

Check if a string is a URL

Isomorphic, functional type-checking for Javascript

A tiny javascript type testing tool

Function argument validation for humans

Detect whether a terminal supports hyperlinks

`util.inspect` with additional type information

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 TypeScript type definitions

Determine a value's type.

Check if your package was installed globally

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

Checks if the given value is a window object.

Check if a value is a function

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

Check if a Buffer/Uint8Array is a ZIP file

Check if a binary is working

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

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

Detect whether the terminal supports Unicode

maximally minimal type-testing library

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

Typescript-compatible minimalistic shallow equality check for arrays/objects

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

Check if a Buffer/Uint8Array is a BZIP2 file

Checks TypeScript types match expected values

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

Check if a binary is working

Update notifications for your CLI app

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

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

Check if a string is a valid JavaScript identifier

Test if a value is a string.

Check if a string is an IP address

Test if a value is an object.

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

Check if the current Linux session is using Wayland

Test if a value is an array.

[![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

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

URI validation functions

Detect the audio type of a Buffer/Uint8Array

Test if a value is object-like.

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

Checks if the given value is a native function.

Check if a URL is relative

Compile TypeScript interfaces into a description that allows runtime validation

Check if a file exists without try catch

Test if a value is a regular expression.

Test if a value is a boolean.

Test if a value is a function.

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

Test if a value is a Float64Array.

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 value is a Uint32Array.

Test if a value is a Float32Array.

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

Test if a value is a Buffer object.

Test if a value is a plain object.

Test if a value is a number.

Test if a value is a Uint8Array.

Test if a value is a Uint16Array.

Returns true if the value passed is all whitespace.

Match BCP 47 language tags with language ranges per RFC 4647

hast utility to check if a node has a property

Binary wrapper for Flow - A static type checker for JavaScript

Check whether a value is "empty".

ESLint shareable config for XO

Check if browser is Firefox

JavaScript Standard Style JSX support - ESLint Shareable Config

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

Check if a process is running

TypeScript Standard Style based on StandardJS

Standard assertion utilities.

Is this a bluebird promise I see before me?

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

Check if your code is running as an npm script

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

Binary wrapper that makes your programs seamlessly available as local dependencies

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

Returns `true` if text is upper case only.

Checks if the given value is null or undefined

Returns `true` if text is lower case only

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

Check if a number is a redirect HTTP status code

Check whether a binary exists in the PATH environment variable

Check if a string only contains alphanumeric characters

Test whether a path exists on the filesystem.

find undeclared identifiers and property accesses in a javascript file.

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

Detect file type by signature

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

Check if a file path is a video file

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

Check if browser is Internet Explorer

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

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

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

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

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

Check if mobile browser.

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check if the current node version has async_hooks.

Check if a Buffer/Uint8Array is a FLAC file.

Test if a finite numeric value is an odd number.

Aids humans and automation in managing npm audit results

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

Check if a value is a natural number

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

Check if a Buffer/Uint8Array is a MP3 file.

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

Check if a Buffer/Uint8Array is a m4a file.

Check if a Buffer/Uint8Array is a wav file.

Type checking for .eslintrc.json

is-iojs determines if runtime is io.js.

Check if a string is a valid filename

check if an AST node is a function of some sort

Verify if something is a Promise

Check if the machine is running Windows or not.

Check whether a RegExp flag is supported

Validates if a value is a JavaScript object.

Validates if a value is undefined.

unist utility to recursively walk over nodes, with ancestral information

Run your TypeScript type tests using Jest

Check whether a package or organization name is available on npm

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

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

Test if an object has a specified property.

Check if a Buffer/Uint8Array is an OGG file.

Check if an environment is big endian.

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

Determine the name of a value's constructor.

Test if a finite numeric value is an even number.

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

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

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

Test if a value is a regular expression string.

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

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

micromark extension to support GFM task list items

Type checking for tsconfig.json

Check if an environment is little endian.

Checks if the file path is zip file. It does not read the complete file nor it depends upon file extension

Create JSON Schema validator from TypeScript.

Check for outdated, incorrect, and unused dependencies.

Check if a string is HTML

Determine the specification defined classification of an object.

Test if a value is NaN.

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

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

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

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

mdast extension to parse and serialize GFM task list items

Check if a string is an IP address

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

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

Test if a value is a Uint8ClampedArray.

A CommonJS port from the ESM file-type package. Now fixed to not have 'tarHeaderChecksumMatches' error!

Test if a value is an Int16Array.

Check if a buffer/Uint8Array is a woff2 file

An *Ackchyually* browser compatible file-type hacky replacement of the `file-type` package. Forked from https://github.com/sindresorhus/file-type

Minimal JavaScript type checking library

Library to check variable type and properties in object.

Test if a value is an Int32Array.

Promisified version of node-which

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

Check if the process is running in an SSH session

Check if a file is a directory

Check if Electron is running in development

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

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

Test if a value is a collection.

Test if a value is an Int8Array.

Checks if a given object is iterable

Test if a value is an arguments object.

ECMAScript feature and API detection

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

JavaScript Standard Style React/JSX support - ESLint Shareable Config

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

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

JavaScript/TypeScript linter (ESLint wrapper) with great defaults

Test if a value is array-like.

Test if a value is an array-like object.

Check if an Array is sorted

Test if a value is an Error object.

Is given string a language code (as per IANA)

A gulp plugin for processing files with ESLint

Check if a String/Buffer is TTF

A straightforward implementation of base58-check encoding

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