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# 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 -->