Revision 1064898 of SyntaxError: JSON.parse: bad parsing

<div>{{jsSidebar("Errors")}}</div>

<h2 id="Message">Message</h2>

<pre class="syntaxbox">
SyntaxError: JSON.parse: unexpected character at line x column y of the JSON data.

SyntaxError: JSON.parse: unexpected end of data at line x column y of the JSON data.

SyntaxError: JSON.parse: expected property name or '}' at line x column y of the JSON data

SyntaxError: JSON.parse: expected ',' or '}' after property value in object at line x column y of the JSON data

SyntaxError: JSON.parse: unterminated fractional number at line 1 column 2 of the JSON data.
</pre>

<h2 id="Error_type">Error type</h2>

<p>{{jsxref("SyntaxError")}}</p>

<h2 id="What_went_wrong">What went wrong?</h2>

<p>{{jsxref("JSON.parse()")}} parses a string as JSON. This string has to be valid JSON and will throw this error if incorrect syntax was encountered.</p>

<h2 id="Examples">Examples</h2>

<h3 id="JSON.parse()_does_not_allow_trailing_commas"><code>JSON.parse()</code> does not allow trailing commas</h3>

<p>Both lines will throw a SyntaxError:</p>

<pre class="example-bad brush: js example-bad">
JSON.parse('[1, 2, 3, 4, ]');
JSON.parse('{"foo" : 1, }');
// SyntaxError JSON.parse: unexpected character at line 1 column 14 of the JSON data
</pre>

<p>Omit the trailing commas to parse the JSON correctly:</p>

<pre class="example-bad brush: js example-good">
JSON.parse('[1, 2, 3, 4 ]');
JSON.parse('{"foo" : 1 }');</pre>

<h3>Property names must be double-quoted strings</h3>

<p>You cannot use single-quotes around properties, like 'foo'.</p>

<pre class="example-bad brush: js example-bad">
JSON.parse("{'foo' : 1 }");
// SyntaxError: JSON.parse: expected property name or '}' at line 1 column 2 of the JSON data</pre>

<p>Instead write "foo":</p>

<pre class="example-bad brush: js example-good">
JSON.parse('{"foo" : 1 }');</pre>

<h3>Leading zeros and decimal points</h3>

<p>You cannot use leading zeros, like 01, and decimal points must be followed by at least one digit.</p>

<pre class="example-bad brush: js example-bad">
JSON.parse('{"foo" : 01 }');
// SyntaxError: JSON.parse: expected ',' or '}' after property value in object at line 1 column 2 of the JSON data

JSON.parse('{"foo" : 1. }'); 
// SyntaxError: JSON.parse: unterminated fractional number at line 1 column 2 of the JSON data
</pre>

<p>Instead write just 1 without a zero and use at least one digit after a decimal point:</p>

<pre class="example-bad brush: js example-good">
JSON.parse('{"foo" : 1 }');
JSON.parse('{"foo" : 1.0 }');
</pre>

<h2 id="See_also">See also</h2>

<ul>
 <li>{{jsxref("JSON")}}</li>
 <li>{{jsxref("JSON.parse()")}}</li>
 <li>{{jsxref("JSON.stringify()")}}</li>
</ul>