types.js

types.js

A tiny (1.7kb), but essential Javascript type checking library.

Especially in non-typed scripting languages like Javascript, proper manual type checking is crucial. Because type checking in Javascript is so confusing and contradictory sometimes, I decided to make a definitive library for myself, with for me understandable/useful standards.

Standard Javascript (NaN !== NaN) == true still freakes me out, I just don't like it. With types.js I can now test NaN with: Types.isNaN(NaN) or Types.typeof( parseInt('Not A Number!') ) === 'nan', both will return true.

Object is another one; typeof ['array'] renders 'object' in standard JS. So if we want to know if some input is a 'real Object', we are constantly fooled by typeof returning 'object' for [], null and /regexp/. With types.js the latter returns 'array', 'null' and 'regexp' respectively.

Be careful with using types.js for variables created with new Number() or other non-literal instantiations. No support for them, because I don't want to get 'number' on Types.typeof( new Number(10) ), as it actually is an object where you can add stuff to.

I've added support for multiple arguments so we can test for multiple values in one call. For save variable instantiation/usage or save function calls I added forceType, ideal for testing a value and setting it (or a replacement) to a variable in a definite type, in one statement.

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For use with node.js you can install with npm install types.js

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Basic usage:

forceString Forces a value to be of a given type, and returns that value, a replacement, or it's literal default.

isString and notString (and the other is and not-types) are useful for single argument type checking.

allString (and the other all-types) are useful for checking if all given arguments are of a certain type.

hasString (and the other has-types) are useful for checking if one or more arguments are of a certain type.

typeof Returns a lowercase string representation of the type of the argument value, according to types.js type-definitions.

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some examples:

var _= Types;									// browser
var _= require( 'types.js' );					// in node.js with npm

var x;
x= _.forceString();								// (empty String)
x= _.forceString( null, 'ok' );					// ok (as String)
x= _.forceString( null, [1, 2, 3] );			// (empty String (== default literal) )
x= _.forceString(33);							// 33 (as String)
x= _.forceNumber('35px');						// 35 (as Number)
x= _.forceNumber( true, function(){} );			// 0 (as Number)
x= _.forceBoolean('35px');						// false (as Boolean)

MyObject= function( data ){
	this.data= _.forceString( data );			// (empty string if data is not of type string or number)
	// or
	this.data= _.forceString( data, 'default init');	// default init
}

var invalidMethod= null;
_.forceFunction( invalidMethod, function(){
	return 'replacement function used.';
 })();											// replacement function used

 x= _.forceFunction( invalidMethod, /regexp/ )();	// (default empty/nop function is called)

x= _.isString( 'Hello types.js!' );				// true
x= _.isString( 23456 );							// false
x= _.isBoolean( false );						// true
x= _.isArray( [1,2,3] );						// true
x= _.isObject( [1,2,3] );						// false
x= _.isObject( /myRegExp/g );					// false
x= _.isNaN( parseInt('generate NaN') );			// true

x= _.notNull('');								// true
x= _.notUndefined( undefined );					// false

x= _.allString( '', " ", 'with text' );						// true
x= _.allString( '', ' ', 'with text', 123 );				// false
x= _.allStringOrNumber( '', ' ', 'with text', 123 );		// true
x= _.allObject( { key: 'nice' }, [], /regexp/ig );			// false
x= _.allArray( [1,2,3], [{}], new RegExp('stop') );			// false
x= _.allArray( [1,2,3], [{}], [false, true] );				// true

x= _.hasString( 123, { value: 'nice' }, ['?'] );			// false
x= _.hasStringOrNumber( [1,2], /reg/, 'true' )				// true
x= _.hasFunction( 123, { value: 'nice' }, function(){} );	// true
x= _.hasUndefined( 'render false!', 123, null );			// false
x= _.hasUndefined( 'render true!', 123, undefined );		// true

x= _.typeof( [1,2,3] );										// 'array'
x= _.typeof( null );										// 'null'
x= _.typeof( parseInt('generate NaN') );					// 'nan'
x= _.typeof( new Date() );									// 'date'
// etc..

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API

Types.parseIntBase

<Number> parseIntBase= 10

Holds the Radix used by forceNumber, defaults to decimals. Can be set to valid radixes for parseInt().

Types.forceBoolean

<String> Types.forceBoolean( value, replacement )

Returns value if value is of type Boolean. Otherwise it will try to convert value to be a Boolean. If that fails too, replacement will be tested for, or converted to, 'boolean' if possible. If that fails, the default types.js boolean literal is returned: a Boolean false

Types.forceString Types.forceNumber Types.forceArray Types.forceObject Types.forceFunction

Just like forceBoolean, only applying the type denoted by the method name. See the forceType literals for the different methods below.

Types.typeof

<String> Types.typeof( value )

Returns a lowercase string representation of the type of value, according to types.js types. See all types.js type-definitions below.

Types.isBoolean

<Boolean> Types.isBoolean( value )

Returns true if the given argument is a Boolean true or false

Types.notBoolean

<Boolean> Types.isBoolean( value )

Returns true if the given argument is not a Boolean true or false

Types.hasBoolean

<Boolean> Types.hasBoolean( values, [value1, ..., valueN])

Returns true if any of the given arguments is a Boolean true or false

Types.allBoolean

<Boolean> Types.allBoolean( values, [value1, ..., valueN])

Returns true only if all given arguments are either a Boolean true or false

All remaining methods are equal to the last four above, except for that they differ in the type being checked. The complete list of all these methods:

not	is	has	all
notBoolean	isBoolean	hasBoolean	allBoolean
notString	isString	hasString	allString
notNumber	isNumber	hasNumber	allNumber
notStringOrNumber	isStringOrNumber	hasStringOrNumber	allStringOrNumber
notObject	isObject	hasObject	allObject
notArray	isArray	hasArray	allArray
notFunction	isFunction	hasFunction	allFunction
notRegexp	isRegexp	hasRegexp	allRegexp
notDate	isDate	hasDate	allDate
notNull	isNull	hasNull	allNull
notUndefined	isUndefined	hasUndefined	allUndefined
notNaN	isNaN	hasNaN	allNaN

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types.js type definitions:

'boolean', 'string', 'number', 'object', 'array', 'function', 'regexp', 'date', 'null', 'undefined', 'nan', 'unknown'

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force'Type' method and default literals

format: <'Type'> force'Type'( <any type> value, <'Type'> replacement )

The literals returned by default:

forceBoolean	forceString	forceNumber	forceObject	forceArray	forceFunction
false	''	0	{}	[]	function(){}