defining a numeric type that allows up to 2 decimal places

[Donal Murtagh]

I'm trying to define a JSON schema for a property

money: 12.12

My main concern is that a maximum of 2 decimal places should be allowed. My initial attempt at defining this field was

money: {
  type: 'number',
  minimum: 0,
  multipleOf: 0.01
}

However, owing to floating point imprecision this fails. For example, using the tv4 validator, the number 147.41 passes validation, but 147.42 fails.

Is there an alternative way to define a numeric type which will only allow a maximum of 2 decimal places?

It seems that the purpose of the "format" attribute is to implement these types of restrictions, but if I define the field like so:

money: {
  type: 'number',
  format: 'currency',
  minimum: 0
}

Then how do I specify that fields with a 'currency' format should only allow up to 2 decimal places?

Thanks in advance.

[Henry Andrews]

See https://github.com/json-schema-org/json-schema-spec/issues/152

[Austin William Wright]

"multipleOf" is the correct keyword to be using for this case, the problem you're running into is a a limitation of the validator trying to validate a 64-bit IEEE floating point (as parsed by JSON.parse) instead of validating the original JSON document. JSON Schema is only defined over a text JSON document.

However, I would consider dropping this keyword altogether, as it varies currency by currency, and even for US Dollars sometimes you need to deal in fractions of a cent.

Austin.