Determine a value's type.
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> Determine a value's type.
``bash`
npm install @stdlib/utils-type-of
`javascript`
var typeOf = require( '@stdlib/utils-type-of' );
#### typeOf( value )
Returns a value's type.
`javascript
var str = typeOf( 'a' );
// returns 'string'
str = typeOf( 5 );
// returns 'number'
`
| description | value | type | notes |
| --------------------- | ----------------------------------- | --------------------- | ------------ |
| string | 'beep' | 'string' | |5
| number | | 'number' | |NaN
| NaN | | 'number' | |+infinity
| infinity | /-infinity | 'number' | |true
| boolean | /false | 'boolean' | |null
| null | | 'null' | |undefined
| undefined | | 'undefined' | |['beep', 5]
| array | | 'array' | |{'foo': 'bar'}
| object | | 'object' | |function (){}
| function | | 'function' | |Symbol()
| symbol | | 'symbol' | ES2015 |/./
| regexp | | 'regexp' | Android 4.1+ |new String('beep')
| String | | 'string' | |new Number(5)
| Number | | 'number' | |new Boolean(false)
| Boolean | | 'boolean' | |new Object()
| Object | | 'object' | |new Array()
| Array | | 'array' | |new Int8Array()
| Int8Array | | 'int8array' | |new Uint8Array()
| Uint8Array | | 'uint8array' | |new Uint8ClampedArray()
| Uint8ClampedArray | | 'uint8clampedarray' | |new Int16Array()
| Int16Array | | 'int16array' | |new Uint16Array()
| Uint16Array | | 'uint16array' | |new Int32Array()
| Int32Array | | 'int32array' | |new Uint32Array()
| Uint32Array | | 'uint32array' | |new Float32Array()
| Float32Array | | 'float32array' | |new Float64Array()
| Float64Array | | 'float64array' | |new ArrayBuffer()
| ArrayBuffer | | 'arraybuffer' | |new Buffer()
| Buffer | | 'buffer' | Node.js |new Date()
| Date | | 'date' | |new RegExp('.')
| RegExp | | 'regexp' | Android 4.1+ |new Function('x', 'return x')
| Function | | 'function' | |new Map()
| Map | | 'map' | ES2015 |new WeakMap()
| WeakMap | | 'weakmap' | ES2015 |new Set()
| Set | | 'set' | ES2015 |new WeakSet()
| WeakSet | | 'weakset' | ES2015 |new Error()
| Error | | 'error' | |new TypeError()
| TypeError | | 'typeerror' | |new SyntaxError()
| SyntaxError | | 'syntaxerror' | |new ReferenceError()
| ReferenceError | | 'referenceerror' | |new URIError()
| URIError | | 'urierror' | |new RangeError()
| RangeError | | 'rangeerror' | |new EvalError()
| EvalError | | 'evalerror' | |Math
| Math | | 'math' | |JSON
| JSON | | 'json' | IE8+ |(function(){return arguments;})()
| arguments | | 'arguments' | IE9+ |new Beep()
| custom constructor | | 'beep' | |new (function(){})()
| anonymous constructor | | '' | |
`javascript
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 ''
`
*
- [@stdlib/utils-constructor-name][@stdlib/utils/constructor-name]: determine the name of a value's constructor.
- [@stdlib/utils-native-class][@stdlib/utils/native-class]: determine the specification defined classification of an object.
*
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
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---
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Copyright © 2016-2026. The Stdlib [Authors][stdlib-authors].
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[deno-url]: https://github.com/stdlib-js/utils-type-of/tree/deno
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[esm-url]: https://github.com/stdlib-js/utils-type-of/tree/esm
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