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getPrototypeOf

Return the prototype of a provided object.

Installation

npm install @stdlib/utils-get-prototype-of

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var getPrototypeOf = require( '@stdlib/utils-get-prototype-of' );

getPrototypeOf( value )

Returns the prototype of an input value.

var proto = getPrototypeOf( {} );
// returns {}

Notes

• In contrast to the native Object.getPrototypeOf, this function does not throw when provided null or undefined. Instead, similar to when provided any value with no inherited properties, the function returns null.

  var proto = getPrototypeOf( Object.create( null ) );
  // returns null
  
  proto = getPrototypeOf( null );
  // returns null
  
  proto = getPrototypeOf( void 0 );
  // returns null

• Value arguments other than null or undefined are coerced to objects.

  var proto = getPrototypeOf( 'beep' );
  // returns String.prototype
  
  proto = getPrototypeOf( 5 );
  // returns Number.prototype

  This behavior matches ES6/ES2015 native Object.getPrototypeOf behavior. In ES5, the native Object.getPrototypeOf throws when provided non-object values.

Examples

var getPrototypeOf = require( '@stdlib/utils-get-prototype-of' );

var proto = getPrototypeOf( 'beep' );
// returns String.prototype

proto = getPrototypeOf( 5 );
// returns Number.prototype

proto = getPrototypeOf( true );
// returns Boolean.prototype

proto = getPrototypeOf( null );
// returns null

proto = getPrototypeOf( void 0 );
// returns null

proto = getPrototypeOf( [] );
// returns Array.prototype

proto = getPrototypeOf( {} );
// returns {}

proto = getPrototypeOf( function foo() {} );
// returns Function.prototype

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See Also

• @stdlib/assert-is-prototype-of: test if an object's prototype chain contains a provided prototype.

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Notice

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.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2025. The Stdlib Authors.