Some numbers are generated as strings when using multipleOf with exponential notation

[michaelmior]

Schema

{
  "type": "number",
  "multipleOf": 1e-8,
  "minimum": 0,
  "maximum": 1
}

Generated JSON

"2e-8"

I expect that this would generate a valid number, instead of a string.

[michaelmior]

I see that the number generator uses toExponential, which explicitly converts results to a string. There seems to be some attempt to perform special handling of multipleOf less than 1, but it seems to be broken.

[michaelmior]

On further investigation, it seems like there is a related bug with is-my-json-valid.

$ node
> const validator = require('is-my-json-valid')
> validator({"type": "number", "multipleOf": 1e-8, "maximum": 1000000000})(736329017)
false

736329017 is indeed a valid multiple of 1e-8.

Update: It is a known issue. See mafintosh/is-my-json-valid#192.

[pateketrueke]

Very nice issue! I think this would take more time as we need to investigate it properly.

[michaelmior]

@pateketrueke I tried removing the call to toExponential, which solved this bug but then introduced another failure because of the bug in is-my-json-valid. I think removing toExponential may be the correct fix once the is-my-json-valid bug is also fixed.