@stdlib/utils/get-prototype-of/lib/polyfill.js

Standard utilities.

/**
* @license Apache-2.0
*
* Copyright (c) 2018 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

// MODULES //

var nativeClass = require( './../../native-class' );
var getProto = require( './proto.js' );


// MAIN //

/**
* Returns the prototype of a provided object.
*
* @private
* @param {Object} obj - input object
* @returns {(Object|null)} prototype
*/
function getPrototypeOf( obj ) {
	var proto = getProto( obj );
	if ( proto || proto === null ) {
		return proto;
	}
	if ( nativeClass( obj.constructor ) === '[object Function]' ) {
		// May break if the constructor has been tampered with...
		return obj.constructor.prototype;
	}
	if ( obj instanceof Object ) {
		return Object.prototype;
	}
	// Return `null` for objects created via `Object.create( null )`. Also return `null` for cross-realm objects on browsers that lack `__proto__` support, such as IE < 11.
	return null;
}


// EXPORTS //

module.exports = getPrototypeOf;