Constructor Name

Determine the name of a value's constructor.

Usage

var constructorName = require( '@stdlib/utils/constructor-name' );

constructorName( value )

Returns the name of a value's constructor.

var v = constructorName( 'a' );
// returns 'String'

v = constructorName( 5 );
// returns 'Number'

function Beep() {
    return this;
}
v = constructorName( new Beep() );
// returns 'Beep'
descriptionvalueconstructornotes
string'beep''String'
number5'Number'
NaNNaN'Number'
infinity+infinity/-infinity'Number'
booleantrue/false'Boolean'
nullnull'Null'
undefinedundefined'Undefined'
array['beep', 5]'Array'
object{'foo': 'bar'}'Object'
functionfunction (){}'Function'
symbolSymbol()'Symbol'ES2015
regexp/./'RegExp'Android 4.1+
Stringnew String('beep')'String'
Numbernew Number(5)'Number'
Booleannew Boolean(false)'Boolean'
Objectnew Object()'Object'
Arraynew Array()'Array'
Int8Arraynew Int8Array()'Int8Array'
Uint8Arraynew Uint8Array()'Uint8Array'
Uint8ClampedArraynew Uint8ClampedArray()'Uint8ClampedArray'
Int16Arraynew Int16Array()'Int16Array'
Uint16Arraynew Uint16Array()'Uint16Array'
Int32Arraynew Int32Array()'Int32Array'
Uint32Arraynew Uint32Array()'Uint32Array'
Float32Arraynew Float32Array()'Float32Array'
Float64Arraynew Float64Array()'Float64Array'
ArrayBuffernew ArrayBuffer()'ArrayBuffer'
Buffernew Buffer()'Buffer'Node.js
Datenew Date()'Date'
RegExpnew RegExp('.')'RegExp'Android 4.1+
Functionnew Function('x', 'return x')'Function'
Mapnew Map()'Map'ES2015
WeakMapnew WeakMap()'WeakMap'ES2015
Setnew Set()'Set'ES2015
WeakSetnew WeakSet()'WeakSet'ES2015
Errornew Error()'Error'
TypeErrornew TypeError()'TypeError'
SyntaxErrornew SyntaxError()'SyntaxError'
ReferenceErrornew ReferenceError()'ReferenceError'
URIErrornew URIError()'URIError'
RangeErrornew RangeError()'RangeError'
EvalErrornew EvalError()'EvalError'
MathMath'Math'
JSONJSON'JSON'IE8+
arguments(function(){return arguments;})()'Arguments'IE9+
custom constructornew Beep()'Beep'
anonymous constructornew (function(){})()''

Notes

  • If a value's constructor is an anonymous function, the implementation returns an empty string.

    var Beep = function () {
        return this;
    };
    
    var v = constructorName( new Beep() );
    // returns ''
    

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 Buffer = require( '@stdlib/buffer/ctor' );
var Symbol = require( '@stdlib/symbol/ctor' );
var constructorName = require( '@stdlib/utils/constructor-name' );

function noop() {
    // Do nothing...
}

var v = constructorName( 'a' );
// returns 'String'

v = constructorName( 5 );
// returns 'Number'

v = constructorName( NaN );
// returns 'Number'

v = constructorName( null );
// returns 'Null'

v = constructorName( void 0 );
// returns 'Undefined'

v = constructorName( true );
// returns 'Boolean'

v = constructorName( false );
// returns 'Boolean'

v = constructorName( {} );
// returns 'Object'

v = constructorName( [] );
// returns 'Array'

v = constructorName( noop );
// returns 'Function'

v = constructorName( /./ );
// returns 'RegExp'

v = constructorName( new Date() );
// returns 'Date'

v = constructorName( new Map() );
// returns 'Map'

v = constructorName( new WeakMap() );
// returns 'WeakMap'

v = constructorName( new Set() );
// returns 'Set'

v = constructorName( new WeakSet() );
// returns 'WeakSet'

v = constructorName( Symbol( 'beep' ) );
// returns 'Symbol'

v = constructorName( new Error() );
// returns 'Error'

v = constructorName( new TypeError() );
// returns 'TypeError'

v = constructorName( new SyntaxError() );
// returns 'SyntaxError'

v = constructorName( new URIError() );
// returns 'URIError'

v = constructorName( new RangeError() );
// returns 'RangeError'

v = constructorName( new ReferenceError() );
// returns 'ReferenceError'

v = constructorName( new EvalError() );
// returns 'EvalError'

v = constructorName( new Int8Array() );
// returns 'Int8Array'

v = constructorName( new Uint8Array() );
// returns 'Uint8Array'

v = constructorName( new Uint8ClampedArray() );
// returns 'Uint8ClampedArray'

v = constructorName( new Int16Array() );
// returns 'Int16Array'

v = constructorName( new Uint16Array() );
// returns 'Uint16Array'

v = constructorName( new Int32Array() );
// returns 'Int32Array'

v = constructorName( new Uint32Array() );
// returns 'Uint32Array'

v = constructorName( new Float32Array() );
// returns 'Float32Array'

v = constructorName( new Float64Array() );
// returns 'Float64Array'

v = constructorName( new ArrayBuffer() );
// returns 'ArrayBuffer'

v = constructorName( new Buffer( 'beep' ) );
// returns 'Buffer'

v = constructorName( Math );
// returns 'Math'

v = constructorName( JSON );
// returns 'JSON'

function Person1() {
    return this;
}
v = constructorName( new Person1() );
// returns 'Person1'

var Person2 = function () {
    return this;
};
v = constructorName( new Person2() );
// returns ''