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stdlib/lib/node_modules/@stdlib/utils/type-of at develop · stdlib-js/stdlib

typeOf

Determine a value's type.

Usage

var typeOf = require( '@stdlib/utils/type-of' );

typeOf( value )

Returns a value's type.

var str = typeOf( 'a' );
// returns 'string'

str = typeOf( 5 );
// returns 'number'
description value type notes
string 'beep' 'string'
number 5 'number'
NaN NaN 'number'
infinity +infinity/-infinity 'number'
boolean true/false 'boolean'
null null 'null'
undefined undefined 'undefined'
array ['beep', 5] 'array'
object {'foo': 'bar'} 'object'
function function (){} 'function'
symbol Symbol() 'symbol' ES2015
regexp /./ 'regexp' Android 4.1+
String new String('beep') 'string'
Number new Number(5) 'number'
Boolean new Boolean(false) 'boolean'
Object new Object() 'object'
Array new Array() 'array'
Int8Array new Int8Array() 'int8array'
Uint8Array new Uint8Array() 'uint8array'
Uint8ClampedArray new Uint8ClampedArray() 'uint8clampedarray'
Int16Array new Int16Array() 'int16array'
Uint16Array new Uint16Array() 'uint16array'
Int32Array new Int32Array() 'int32array'
Uint32Array new Uint32Array() 'uint32array'
Float32Array new Float32Array() 'float32array'
Float64Array new Float64Array() 'float64array'
ArrayBuffer new ArrayBuffer() 'arraybuffer'
Buffer new Buffer() 'buffer' Node.js
Date new Date() 'date'
RegExp new RegExp('.') 'regexp' Android 4.1+
Function new Function('x', 'return x') 'function'
Map new Map() 'map' ES2015
WeakMap new WeakMap() 'weakmap' ES2015
Set new Set() 'set' ES2015
WeakSet new WeakSet() 'weakset' ES2015
Error new Error() 'error'
TypeError new TypeError() 'typeerror'
SyntaxError new SyntaxError() 'syntaxerror'
ReferenceError new ReferenceError() 'referenceerror'
URIError new URIError() 'urierror'
RangeError new RangeError() 'rangeerror'
EvalError new EvalError() 'evalerror'
Math Math 'math'
JSON JSON 'json' IE8+
arguments (function(){return arguments;})() 'arguments' IE9+
custom constructor new Beep() 'beep'
anonymous constructor new (function(){})() ''

Examples

var Float32Array = require( '@stdlib/array/float32' );
var Float64Array = require( '@stdlib/array/float64' );
var Int8Array = require( '@stdlib/array/int8' );
var Int16Array = require( '@stdlib/array/int16' );
var Int32Array = require( '@stdlib/array/int32' );
var Uint8Array = require( '@stdlib/array/uint8' );
var Uint8ClampedArray = require( '@stdlib/array/uint8c' );
var Uint16Array = require( '@stdlib/array/uint16' );
var Uint32Array = require( '@stdlib/array/uint32' );
var ArrayBuffer = require( '@stdlib/array/buffer' );
var Symbol = require( '@stdlib/symbol/ctor' );
var typeOf = require( '@stdlib/utils/type-of' );

var str = typeOf( 'a' );
// returns 'string'

str = typeOf( 5 );
// returns 'number'

str = typeOf( NaN );
// returns 'number'

str = typeOf( Infinity );
// returns 'number'

str = typeOf( true );
// returns 'boolean'

str = typeOf( false );
// returns 'boolean'

str = typeOf( void 0 );
// returns 'undefined'

str = typeOf( null );
// returns 'null'

str = typeOf( [] );
// returns 'array'

str = typeOf( {} );
// returns 'object'

str = typeOf( function noop() {} );
// returns 'function'

str = typeOf( new Map() );
// returns 'map'

str = typeOf( new WeakMap() );
// returns 'weakmap'

str = typeOf( new Set() );
// returns 'set'

str = typeOf( new WeakSet() );
// returns 'weakset'

str = typeOf( Symbol( 'beep' ) );
// returns 'symbol'

str = typeOf( new Error( 'beep' ) );
// returns 'error'

str = typeOf( new TypeError( 'beep' ) );
// returns 'typeerror'

str = typeOf( new SyntaxError( 'beep' ) );
// returns 'syntaxerror'

str = typeOf( new ReferenceError( 'beep' ) );
// returns 'referenceerror'

str = typeOf( new URIError( 'beep' ) );
// returns 'urierror'

str = typeOf( new EvalError( 'beep' ) );
// returns 'evalerror'

str = typeOf( new RangeError( 'beep' ) );
// returns 'rangeerror'

str = typeOf( new Date() );
// returns 'date'

str = typeOf( /./ );
// returns 'regexp'

str = typeOf( Math );
// returns 'math'

str = typeOf( JSON );
// returns 'json'

str = typeOf( new Int8Array( 10 ) );
// returns 'int8array'

str = typeOf( new Uint8Array( 10 ) );
// returns 'uint8array'

str = typeOf( new Int16Array( 10 ) );
// returns 'int16array'

str = typeOf( new Uint16Array( 10 ) );
// returns 'uint16array'

str = typeOf( new Int32Array( 10 ) );
// returns 'int32array'

str = typeOf( new Uint32Array( 10 ) );
// returns 'uint32array'

str = typeOf( new Float32Array( 10 ) );
// returns 'float32array'

str = typeOf( new Float64Array( 10 ) );
// returns 'float64array'

str = typeOf( new ArrayBuffer( 10 ) );
// returns 'arraybuffer'

function Person1() {
    return this;
}
str = typeOf( new Person1() );
// returns 'person1'

var Person2 = function () {
    return this;
};
str = typeOf( new Person2() );
// returns ''

See Also