107 lines
2.1 KiB
JavaScript
107 lines
2.1 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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// VARIABLES //
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/**
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* Detects a JSON string.
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*
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* Regular expression: `/^\{[\s\S]*\}$|^\[[\s\S]*\]$/`
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*
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* - `^\{`
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*
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* - match a `{` literal which is the first character
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*
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* - `[\s\S]*`
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*
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* - match any whitespace and non-whitespace characters which occur `0` or more times
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*
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* - `\}$`
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*
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* - match a `}` literal which is the last character
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*
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* - `|`
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*
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* - alternatively
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*
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* - `^\[`
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*
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* - match a `[` literal which is the first character
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*
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* - `[\s\S]*`
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*
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* - match any whitespace and non-whitespace characters which occur `0` or more times
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*
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* - `\]$`
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*
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* - match a `]` literal which is the last character
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*
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*
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* Example matching strings:
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*
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* - `'{}'`
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* - `'[]'`
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* - `'{adjlkfaj3743.,><\n\t\rdf}'`
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* - `'[adjlkfaj3743.,><\n\t\rdf]'`
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* - `'{"a":5}'`
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*
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* @constant
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* @type {RegExp}
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* @default /^\{[\s\S]*\}$|^\[[\s\S]*\]$/
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*/
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var re = /^\{[\s\S]*\}$|^\[[\s\S]*\]$/;
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// MAIN //
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/**
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* Tests if a value is a parseable JSON string.
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*
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* @param {*} value - value to test
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* @returns {boolean} boolean indicating if a value is a parseable JSON string
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*
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* @example
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* var v = isJSON( '{"a":5}' );
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* // returns true
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*
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* @example
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* var v = isJSON( '{a":5}' );
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* // returns false
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*/
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function isJSON( value ) {
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if ( typeof value !== 'string' ) {
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return false;
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}
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if ( !re.test( value ) ) {
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return false;
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}
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try {
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JSON.parse( value );
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} catch ( err ) { // eslint-disable-line no-unused-vars
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return false;
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}
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return true;
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}
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// EXPORTS //
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module.exports = isJSON;
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