typechecker

TypeChecker

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

Why?

Why should I use this instead of say instanceof?

Under certain circumstances instanceof may not return the correct results. This occurs with node's vm module especially, and circumstances where an object's prototype has been dereferenced from the original. As such, for basic == and === checks (like a === null), you're fine not using this, but for checks when you would have done instanceof (like err instanceof Error), you should try to use this instead. Plus things like isEmpty, isEmptyObject and isPlainObject are darn useful!

Install

NPM

• Use: require('typechecker')
• Install: npm install --save typechecker

Browserify

• Use: require('typechecker')
• Install: npm install --save typechecker
• CDN URL: //wzrd.in/bundle/typechecker@3.0.0

Ender

• Use: require('typechecker')
• Install: ender add typechecker

Usage

Example

require('typechecker').isRegExp(/^a/)  // returns true

Methods

Helpers:

• getObjectType - returns the object string of the value, e.g. when passed /^a/ it'll return "[object RegExp]"
• getType - returns lower case string of the type, e.g. when passed /^a/ it'll return "regex"

Values:

• isPlainObject - returns true if the value doesn't have a custom prototype
• isEmpty - returns true if the value is null or undefined
• isEmptyObject - returns true if the object has no keys that are its own
• isNativeClass - returns true if the value is a native ES6 class
• isConventionalClass - returns true if the value is a function which name starts with a capital letter

Types:

• isError - returns true if the value is an error, otherwise false
• isDate - returns true if the value is a date, otherwise false
• isArguments - returns true if the value is function arguments, otherwise false
• isClass - returns true if the value is a native or conventional class, otherwise false
• isFunction - returns true if the value is a function, otherwise false
• isRegExp - returns true if the value is a regular expression instance, otherwise false
• isArray - returns true if the value is an array, otherwise false
• isNumber - returns true if the value is a number ("2" is a string), otherwise false
• isString - returns true if the value is a string, otherwise false
• isBoolean - returns true if the value is a boolean, otherwise false
• isNull - returns true if the value is null, otherwise false
• isUndefined - returns true if the value is undefined, otherwise false

History

Discover the change history by heading on over to the HISTORY.md file.

Contribute

Discover how you can contribute by heading on over to the CONTRIBUTING.md file.

Backers

Maintainers

These amazing people are maintaining this project:

• Benjamin Lupton [e-mail] (https://github.com/balupton)

Sponsors

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Contributors

These amazing people have contributed code to this project:

• Benjamin Lupton [e-mail] — view contributions
• joegesualdo — view contributions
• sfrdmn — view contributions

Become a contributor!

License

Unless stated otherwise all works are:

• Copyright © 2013+ Bevry Pty Ltd [e-mail] (http://bevry.me)
• Copyright © 2011-2012 Benjamin Lupton [e-mail] (http://balupton.com)

and licensed under:

• The incredibly permissive MIT License

Changelog

v3.0.0 2015 August 27

• Added new class type that the getType method can now return
• Added the methods:
  • isClass (checks for native and conventional classes)
  • isNativeClass (checks for native ES6 classes)
  • isConventionalClass (checks for functions that start with a capital letter)
• Anonymous compiled/non-native classes may be detected as functions instead of as classes. If you rely on class detection, be aware of this, and document this to your users accordingly.