91 lines
2.1 KiB
Markdown
91 lines
2.1 KiB
Markdown
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<!--
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@license Apache-2.0
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Copyright (c) 2018 The Stdlib Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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# isJSON
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> Test if a value is a parseable JSON string.
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<section class="usage">
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## Usage
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```javascript
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var isJSON = require( '@stdlib/assert/is-json' );
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```
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#### isJSON( value )
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Tests if a `value` is a parseable JSON `string`.
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```javascript
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var value = '{"a":5}';
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var bool = isJSON( value );
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// returns true
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```
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</section>
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<!-- /.usage -->
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<section class="notes">
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## Notes
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- The implementation validates that the input `value` is a `string` literal. For all other inputs, the method returns `false`.
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- The implementation validates that a `string` begins with either `[` or `{` and ends with a corresponding `]` or `}`, respectively. Hence, the method will return `false` for the following `strings`, despite `JSON.parse` accepting their input:
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- `'<number>'` (e.g., `'5'`)
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- `'<boolean>'` (e.g., `'true'`)
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- `'null'`
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- The implementation wraps `JSON.parse` inside a `try/catch`. Hence, this function cannot be optimized by the compiler during runtime. Nevertheless, using this function is better than embedding a `try/catch` within a larger `function` which could be optimized in the absence of a `try/catch`.
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</section>
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<!-- /.notes -->
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<section class="examples">
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## Examples
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<!-- eslint no-undef: "error" -->
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```javascript
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var isJSON = require( '@stdlib/assert/is-json' );
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var bool = isJSON( '{"a":5}' );
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// returns true
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bool = isJSON( '{a":5}' );
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// returns false
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```
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</section>
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<!-- /.examples -->
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<section class="links">
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</section>
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<!-- /.links -->
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