Trailing decimal point in a JSON number
`1.` is valid in C and JavaScript but not in JSON, which requires at least one digit after the decimal point.
The input
{"a": 1.}{"a": 1.0}How to fix it
Write `1.0` or `1`.
Usually produced by trimming trailing zeros with a regex that was too eager.
What each parser reports
Every message below was captured by running this exact input through the parser named. 13 of 21 parsers rejected it; 8 accepted it.
| Parser | Exact message |
|---|---|
| CPython json.loads CPython 3.12.3 | Expecting ',' delimiter: line 1 column 8 (char 7)what this message means → |
| encoding/json Unmarshal Go go1.22.2 | invalid character '}' after decimal point in numeric literalwhat this message means → |
| Gson Java 21.0.12 | accepted — no error |
| Gson JsonParser (lenient off) Java 21.0.12 | accepted — no error |
| hjson Node.js 22.22.2 | accepted — no error |
| Jackson ObjectMapper Java 21.0.12 | Unexpected character ('}' (code 125)) in numeric value: Decimal point not followed by a digitwhat this message means → |
| JavaScriptCore JSON.parse JavaScriptCore (Bun 1.4.1) | JSON Parse error: Invalid digits after decimal pointwhat this message means → |
| json-bigint Node.js 22.22.2 | accepted — no error |
| JSON5 Node.js 22.22.2 | accepted — no error |
| JSON::PP Perl 5.038002 | malformed number (no digits after decimal point), at character offset 9 (before "(end of string)")what this message means → |
| json_decode PHP 8.3.6 | Syntax error |
| Newtonsoft.Json JsonConvert Newtonsoft.Json 13.0.3 on .NET 8.0.30 | accepted — no error |
| Newtonsoft.Json JsonTextReader Newtonsoft.Json 13.0.3 on .NET 8.0.30 | accepted — no error |
| orjson CPython 3.12.3 | no digit after decimal point: line 1 column 9 (char 8)what this message means → |
| Ruby JSON.parse Ruby 3.2.3 | unexpected token at '{"a": 1.}' |
| serde_json::from_str Rust (serde_json 1.x) | invalid number at line 1 column 9what this message means → |
| SpiderMonkey JSON.parse SpiderMonkey 115 | JSON.parse: unterminated fractional number at line 1 column 9 of the JSON datawhat this message means → |
| System.Text.Json Deserialize .NET 8.0.30 | '}' is invalid within a number, immediately after a decimal point ('.'). Expected a digit ('0'-'9'). Path: $ | LineNumber: 0 | BytePositionInLine: 8.what this message means → |
| System.Text.Json JsonDocument .NET 8.0.30 | '}' is invalid within a number, immediately after a decimal point ('.'). Expected a digit ('0'-'9'). LineNumber: 0 | BytePositionInLine: 8.what this message means → |
| ujson CPython 3.12.3 | accepted — no error |
| V8 JSON.parse Node.js 22.22.2 | Unterminated fractional number in JSON at position 8 (line 1 column 9)what this message means → |
What the specification says
The exact sections that govern this error. Descriptions are our paraphrase; follow the links for the normative text.
| Body | Section |
|---|---|
| IETF | A number is base 10, optionally signed with a minus, with an optional fraction and exponent. The section states that leading zeros are not allowed, and that values which cannot be represented in its grammar — Infinity and NaN among them — are not permitted. |
| Ecma International | A number is decimal digits with no superfluous leading zero. Values such as Infinity and NaN are not permitted. |
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