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@stdlib/utils-constructor-name
Advanced tools
@stdlib/utils-constructor-name is a utility package that provides a function to get the name of a constructor for a given value. This can be useful for type checking, debugging, and logging purposes.
Get Constructor Name
This feature allows you to get the name of the constructor for various types of values, including primitives, arrays, objects, and special values like null and undefined.
const constructorName = require('@stdlib/utils-constructor-name');
console.log(constructorName(5)); // 'Number'
console.log(constructorName('hello')); // 'String'
console.log(constructorName([])); // 'Array'
console.log(constructorName({})); // 'Object'
console.log(constructorName(null)); // 'null'
console.log(constructorName(undefined)); // 'undefined'
type-detect is a library that provides a more comprehensive type detection mechanism. It can detect types of built-in objects, user-defined classes, and more. Compared to @stdlib/utils-constructor-name, type-detect offers a broader range of type detection capabilities.
kind-of is another utility for type checking that returns the type of a given value as a string. It supports a wide range of types and is known for its simplicity and performance. While @stdlib/utils-constructor-name focuses on constructor names, kind-of provides a more general type detection.
lodash.isplainobject is a specific utility from the lodash library that checks if a value is a plain object. While it doesn't provide constructor names, it is useful for type checking in scenarios where you need to differentiate between plain objects and other types of objects. It complements the functionality of @stdlib/utils-constructor-name by offering specialized type checks.
We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.
The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.
When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.
To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!
Determine the name of a value's constructor.
npm install @stdlib/utils-constructor-name
var constructorName = require( '@stdlib/utils-constructor-name' );
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 empty string
.
var Beep = function () {
return this;
};
var v = constructorName( new Beep() );
// returns ''
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 ''
@stdlib/utils-function-name
: determine a function's name.This package is part of 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, see the main project repository.
See LICENSE.
Copyright © 2016-2024. The Stdlib Authors.
0.2.2 (2024-07-27)
No changes reported for this release.
</section> <!-- /.release --> <section class="release" id="v0.2.1">FAQs
Determine the name of a value's constructor.
The npm package @stdlib/utils-constructor-name receives a total of 161,651 weekly downloads. As such, @stdlib/utils-constructor-name popularity was classified as popular.
We found that @stdlib/utils-constructor-name demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 4 open source maintainers collaborating on the project.
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