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Determine the name of a value's constructor.
import constructorName from 'https://cdn.jsdelivr.net/gh/stdlib-js/utils-constructor-name@esm/index.mjs';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'| description | value | constructor | 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(){})() |
'' |
-
If a value's constructor is an anonymous
function, the implementation returns an emptystring.var Beep = function () { return this; }; var v = constructorName( new Beep() ); // returns ''
<!DOCTYPE html>
<html lang="en">
<body>
<script type="module">
import Float32Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float32@esm/index.mjs';
import Float64Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@esm/index.mjs';
import Int8Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-int8@esm/index.mjs';
import Int16Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-int16@esm/index.mjs';
import Int32Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-int32@esm/index.mjs';
import Uint8Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-uint8@esm/index.mjs';
import Uint8ClampedArray from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-uint8c@esm/index.mjs';
import Uint16Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-uint16@esm/index.mjs';
import Uint32Array from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-uint32@esm/index.mjs';
import ArrayBuffer from 'https://cdn.jsdelivr.net/gh/stdlib-js/array-buffer@esm/index.mjs';
import Buffer from 'https://cdn.jsdelivr.net/gh/stdlib-js/buffer-ctor@esm/index.mjs';
import Symbol from 'https://cdn.jsdelivr.net/gh/stdlib-js/symbol-ctor@esm/index.mjs';
import constructorName from 'https://cdn.jsdelivr.net/gh/stdlib-js/utils-constructor-name@esm/index.mjs';
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 ''
</script>
</body>
</html>@stdlib/utils-function-name: determine a function's name.
This package is part of stdlib, a standard library 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, see the main project repository.
See LICENSE.
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