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* @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 getPrototypeOf = require( '@stdlib/utils/get-prototype-of' );
var nativeClass = require( '@stdlib/utils/native-class' );
// MAIN //
/**
* Tests if a value is an `Error` object.
*
* @param {*} value - value to test
* @returns {boolean} boolean indicating whether a value is an `Error` object
*
* @example
* var bool = isError( new Error( 'beep' ) );
* // returns true
*
* @example
* var bool = isError( {} );
* // returns false
*/
function isError( value ) {
if ( typeof value !== 'object' || value === null ) {
return false;
}
// Check for `Error` objects from the same realm (same Node.js `vm` or same `Window` object)...
if ( value instanceof Error ) {
return true;
}
// Walk the prototype tree until we find an object having the desired native class...
while ( value ) {
if ( nativeClass( value ) === '[object Error]' ) {
return true;
}
value = getPrototypeOf( value );
}
return false;
}
// EXPORTS //
module.exports = isError;
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