68 lines
1.6 KiB
JavaScript
68 lines
1.6 KiB
JavaScript
/**
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* @license Apache-2.0
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*
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* Copyright (c) 2021 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 isFunction = require( './../../is-function' );
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// VARIABLES //
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var RE_ARROW_FUNCTION = /^(?:\([^)]*\) *|[^=]*)=>/;
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// Using `Function#toString` bypasses a value's own `toString` method to provide an extra, but not security proof, precaution to prevent a provided function from impersonating an arrow function:
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var fcn2str = Function.prototype.toString;
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// MAIN //
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/**
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* Tests whether a value is an arrow function.
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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 arrow function
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*
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* @example
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* var arrow = () => {};
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* var bool = isArrowFunction( arrow );
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* // returns true
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*
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* @example
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* function beep() {
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* return 'beep';
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* }
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*
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* var bool = isArrowFunction( beep );
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* // returns false
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*/
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function isArrowFunction( value ) {
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var str;
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if ( !isFunction( value ) ) {
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return false;
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}
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str = fcn2str.call( value );
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return RE_ARROW_FUNCTION.test( str );
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}
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// EXPORTS //
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module.exports = isArrowFunction;
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