The JavaScript exceptions thrown by JSON.parse() occur when string failed to be parsed as JSON.
The Error Mesages: 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
The cause of problem: 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() dose not allow trailling of commas.
Both lines will throw a SyntaxError:
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:
JSON.parse('[1, 2, 3, 4]');
JSON.parse('{"foo": 1}');EXAMPLES:
Property names must be double quoted strings.
You cannot use single-quotes around properties, like 'foo'.
JSON.parse("{'foo': 1}");
// SyntaxError: JSON.parse: expected property name or '}'
// at line 1 column 2 of the JSON data
Instead write "foo":
JSON.parse('{"foo": 1}');EXAMPLES:
Leading zeros and decimal points.
You cannot use leading zeros, like 01, and decimal points must be followed by at least one digit.
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:
JSON.parse('{"foo": 1}');
JSON.parse('{"foo": 1.0}');