check-types.js

A tiny JavaScript library for checking types and throwing exceptions.

Installation

Via NPM

npm install check-types

Via Jam

jam install check-types

Via Git

git clone git@github.com:philbooth/check-types.js.git

Usage

Loading the library

Both CommonJS (e.g. if you're running on Node.js or in the browser with Browserify) and AMD (e.g. if you're using Require.js) loading styles are supported. If neither system is detected, the library defaults to exporting its interface globally as check.

Calling the exported functions

A number of different functions are exported:

check.quacksLike (thing, duck)

Tests whether an object 'quacks like a duck'. Returns true if the first argument has all of the properties of the second, archetypal argument (the 'duck'). Returns false otherwise. If either argument is not an object, an exception is thrown.

check.verifyQuack (thing, duck, message)

Throws an exception if an object does not 'quack like a duck'.

check.isInstance (thing, prototype)

Returns true if an object is an instance of a prototype, false otherwise.

check.verifyInstance (thing, prototype, message)

Throws an exception if an object is not an instance of a prototype.

check.isEmptyObject (thing)

Returns true if something is an empty, non-null, non-array object, false otherwise.

check.verifyEmptyObject (thing, message)

Throws an exception unless something is an empty, non-null, non-array object.

check.isObject (thing)

Returns true if something is a non-null, non-array object, false otherwise.

check.verifyObject (thing, message)

Throws an exception unless something is a non-null, non-array object.

check.isLength (thing, length)

Returns true if something has a length property that matches the specified length, false otherwise.

check.verifyLength (thing, length, message)

Throws an exception unless something has a length property matching the specified length.

check.isArray (thing)

Returns true something is an array, false otherwise.

check.verifyArray (thing, message)

Throws an exception unless something is an array.

check.isFunction (thing)

Returns true if something is function, false otherwise.

check.verifyFunction (thing, message)

Throws an exception unless something is function.

check.isUnemptyString (thing)

Returns true if something is a non-empty string, false otherwise.

check.verifyUnemptyString (thing, message)

Throws an exception unless something is a non-empty string.

check.isString (thing)

Returns true if something is a string, false otherwise.

check.verifyString (thing, message)

Throws an exception unless something is a string.

check.isPositiveNumber (thing)

Returns true if something is a number greater than zero, false otherwise.

check.verifyPositiveNumber (thing, message)

Throws an exception unless something is a number greater than zero.

check.isNegativeNumber (thing)

Returns true if something is a number less than zero, false otherwise.

check.verifyNegativeNumber (thing, message)

Throws an exception unless something is a number less than zero.

check.isEvenNumber (thing)

Returns true if something is an even number, false otherwise.

check.verifyEvenNumber (thing, message)

Throws an exception unless something is an even number.

check.isOddNumber (thing)

Returns true if something is an even number, false otherwise.

check.verifyOddNumber (thing, message)

Throws an exception unless something is an even number.

check.isNumber (thing)

Returns true if something is a number, false otherwise. In this instance, NaN is not considered a number.

check.verifyNumber (thing, message)

Throws an exception unless something is a number. In this instance, NaN is not considered a number.

Development

Dependencies

The build environment relies on Node.js, NPM, Jake, JSHint, Mocha, Chai and UglifyJS. Assuming that you already have Node.js and NPM set up, you just need to run npm install to install all of the dependencies as listed in package.json.

Unit tests

The unit tests are in test/check-types.js. You can run them with the command npm test or jake jstest.