SyntaxError: JSON.parse: bad parsing
The JavaScript exceptions thrown by JSON.parse() occur when string failed
to be parsed as JSON.
Message
SyntaxError: JSON.parse: unterminated string literal SyntaxError: JSON.parse: bad control character in string literal SyntaxError: JSON.parse: bad character in string literal SyntaxError: JSON.parse: bad Unicode escape SyntaxError: JSON.parse: bad escape character SyntaxError: JSON.parse: unterminated string SyntaxError: JSON.parse: no number after minus sign SyntaxError: JSON.parse: unexpected non-digit SyntaxError: JSON.parse: missing digits after decimal point SyntaxError: JSON.parse: unterminated fractional number SyntaxError: JSON.parse: missing digits after exponent indicator SyntaxError: JSON.parse: missing digits after exponent sign SyntaxError: JSON.parse: exponent part is missing a number SyntaxError: JSON.parse: unexpected end of data SyntaxError: JSON.parse: unexpected keyword SyntaxError: JSON.parse: unexpected character SyntaxError: JSON.parse: end of data while reading object contents SyntaxError: JSON.parse: expected property name or '}' SyntaxError: JSON.parse: end of data when ',' or ']' was expected SyntaxError: JSON.parse: expected ',' or ']' after array element SyntaxError: JSON.parse: end of data when property name was expected SyntaxError: JSON.parse: expected double-quoted property name SyntaxError: JSON.parse: end of data after property name when ':' was expected SyntaxError: JSON.parse: expected ':' after property name in object SyntaxError: JSON.parse: end of data after property value in object SyntaxError: JSON.parse: expected ',' or '}' after property value in object SyntaxError: JSON.parse: expected ',' or '}' after property-value pair in object literal SyntaxError: JSON.parse: property names must be double-quoted strings SyntaxError: JSON.parse: expected property name or '}' SyntaxError: JSON.parse: unexpected character SyntaxError: JSON.parse: unexpected non-whitespace character after JSON data
Error type
SyntaxError
What went wrong?
JSON.parse() parses a string as JSON. This string has to be valid JSON
and will throw this error if incorrect syntax was encountered.
Examples
JSON.parse() does not allow trailing commas
Both lines will throw a SyntaxError:
js
JSON.parse("[1, 2, 3, 4,]");
JSON.parse('{"foo": 1,}');
// SyntaxError JSON.parse: unexpected character
// at line 1 column 14 of the JSON data
Omit the trailing commas to parse the JSON correctly:
js
JSON.parse("[1, 2, 3, 4]");
JSON.parse('{"foo": 1}');
Property names must be double-quoted strings
You cannot use single-quotes around properties, like 'foo'.
js
JSON.parse("{'foo': 1}");
// SyntaxError: JSON.parse: expected property name or '}'
// at line 1 column 2 of the JSON data
Instead write "foo":
js
JSON.parse('{"foo": 1}');
Leading zeros and decimal points
You cannot use leading zeros, like 01, and decimal points must be followed by at least one digit.
js
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
Instead write just 1 without a zero and use at least one digit after a decimal point:
js
JSON.parse('{"foo": 1}');
JSON.parse('{"foo": 1.0}');