Bug #19686: BigDecimal object returns JSON string

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-darwin21]
• Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN

[goh (Goh Matsumoto)]

Hi,

When I call the to_json method to the BigDecimal object, it returns a JSON string.
Is this intentional?

> ruby -v -rbigdecimal -rjson -e 'p BigDecimal("1.2").to_json'
ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-darwin21]
"\"0.12e1\""

> ruby -v -rjson/add/bigdecimal -e 'p BigDecimal("1.2").to_json'
ruby 3.2.2 (2023-03-30 revision e51014f9c0) [x86_64-darwin21]
"{\"json_class\":\"BigDecimal\",\"b\":\"18:0.12e1\"}"

I expect a JSON number like "0.12e1".

[byroot (Jean Boussier)]

• Status changed from Open to Closed

I believe it's intentional as the main point of BigDecimal is to avoid float imprecision issues.

On a tangent, this issue should have been filed in JSON's bug tracker: https://github.com/flori/json/issues, But anyway, changing this would break way too much code so unlikely to happen.

[byroot (Jean Boussier)]

Forgot to say that to fix your issue you can convert BigDecimal with to_f prior to calling to_json.