65 lines
1.6 KiB
JavaScript
65 lines
1.6 KiB
JavaScript
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/**
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* @license Apache-2.0
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*
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* Copyright (c) 2018 The Stdlib Authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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// MODULES //
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var getPrototypeOf = require( '@stdlib/utils/get-prototype-of' );
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var nativeClass = require( '@stdlib/utils/native-class' );
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// MAIN //
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/**
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* Tests if a value is an `Error` object.
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*
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* @param {*} value - value to test
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* @returns {boolean} boolean indicating whether a value is an `Error` object
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*
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* @example
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* var bool = isError( new Error( 'beep' ) );
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* // returns true
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*
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* @example
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* var bool = isError( {} );
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* // returns false
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*/
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function isError( value ) {
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if ( typeof value !== 'object' || value === null ) {
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return false;
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}
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// Check for `Error` objects from the same realm (same Node.js `vm` or same `Window` object)...
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if ( value instanceof Error ) {
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return true;
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}
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// Walk the prototype tree until we find an object having the desired native class...
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while ( value ) {
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if ( nativeClass( value ) === '[object Error]' ) {
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return true;
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}
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value = getPrototypeOf( value );
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}
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return false;
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}
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// EXPORTS //
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module.exports = isError;
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