<!-- @license Apache-2.0 Copyright (c) 2018 The Stdlib Authors. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. --> # Parse JSON > Parse a string as [JSON][json]. <section class="usage"> ## Usage ```javascript var parseJSON = require( '@stdlib/utils/parse-json' ); ``` #### parseJSON( str\[, reviver] ) Parses a `string` as [JSON][json]. ```javascript var out = parseJSON( '{"beep":"boop"}' ); // returns {'beep':'boop'} ``` If unable to parse a `string` as [JSON][json], the function returns an error. ```javascript var out = parseJSON( 'beep' ); // returns <SyntaxError> ``` To transform the `string` being parsed, provide a `reviver`. ```javascript function reviver( key, value ) { if ( key === '' ) { return value; } if ( key === 'beep' ) { return value; } } var str = '{"beep":"boop","a":"b"}'; var out = parseJSON( str, reviver ); // returns {'beep':'boop'} ``` </section> <!-- /.usage --> <section class="notes"> ## Notes - In contrast to the native [`JSON.parse()`][json-parse], this implementation throws a `TypeError` if provided **any** value which is not a `string`. ```javascript var out = JSON.parse( null ); // returns null out = parseJSON( null ); // throws <TypeError> ``` - In contrast to the native [`JSON.parse()`][json-parse], this implementation does **not** throw a `SyntaxError` if unable to parse a `string` as [JSON][json]. ```javascript var out = parseJSON( '{"beep":"boop}' ); // returns <SyntaxError> out = JSON.parse( '{"beep":"boop}' ); // throws <SyntaxError> ``` - In contrast to the native [`JSON.parse()`][json-parse], this implementation throws a `TypeError` if provided a `reviver` argument which is **not** a `function`. ```javascript var out = JSON.parse( '{"a":"b"}', [] ); // returns {'a':'b'} out = parseJSON( '{"a":"b"}', [] ); // throws <TypeError> ``` </section> <!-- /.notes --> <section class="examples"> ## Examples <!-- eslint no-undef: "error" --> ```javascript var parseJSON = require( '@stdlib/utils/parse-json' ); var out; out = parseJSON( '{"beep":"boop"}' ); // returns {'beep':'boop'} out = parseJSON( '3.14' ); // returns 3.14 out = parseJSON( 'true' ); // returns true out = parseJSON( 'null' ); // returns null out = parseJSON( '{"beep":"boop}' ); // returns <SyntaxError> ``` </section> <!-- /.examples --> <section class="links"> [json]: http://www.json.org/ [json-parse]: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse </section> <!-- /.links -->