79 lines
1.9 KiB
JavaScript
79 lines
1.9 KiB
JavaScript
/**
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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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// MAIN //
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/**
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* Tests if two arguments are the same value.
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*
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* ## Notes
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*
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* - The function implements the [SameValue Algorithm][ecma-262-same-value-algorithm], as specified in ECMAScript 5.
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* - In contrast to the strict equality operator `===`, `-0` and `+0` are distinguishable and `NaNs` are the same.
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*
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* [ecma-262-same-value-algorithm]: http://ecma-international.org/ecma-262/5.1/#sec-9.12
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*
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* @param {*} a - first input value
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* @param {*} b - second input value
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* @returns {boolean} boolean indicating whether two arguments are the same value
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*
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* @example
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* var bool = isSameValue( true, true );
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* // returns true
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*
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* @example
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* var bool = isSameValue( 3.14, 3.14 );
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* // returns true
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*
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* @example
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* var bool = isSameValue( {}, {} );
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* // returns false
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*
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* @example
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* var bool = isSameValue( -0.0, -0.0 );
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* // returns true
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*
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* @example
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* var bool = isSameValue( -0.0, 0.0 );
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* // returns false
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*
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* @example
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* var bool = isSameValue( NaN, NaN );
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* // returns true
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*
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* @example
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* var bool = isSameValue( [], [] );
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* // returns false
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*/
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function isSameValue( a, b ) {
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if ( a === b ) {
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if ( a === 0.0 ) {
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return 1.0 / a === 1.0 / b; // handles +-0
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}
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return true;
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}
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return ( a !== a && b !== b ); // handles NaNs
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}
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// EXPORTS //
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module.exports = isSameValue;
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