Floating point when using multipleOf

[adelura]

Hi, I just started to play with your library and noticed one thing:

let jsf = require('json-schema-faker');
let seed = [ 0.25546874766962246, 0.06559633646612273 ];
jsf.option({ random: () =>seed.shift() });

let schema = {
  "type": "number",
  "multipleOf": 0.01
};

jsf.resolve(schema).then(function(sample) {
  console.log(sample); // 13119267.290000001
});

What I expect here is two decimal places at most. I can imagine that you might be aware of that as this project looks mature, but I couldn't find any issue related to that.

[pateketrueke]

Nice issue, you're totally right, it should generate a two-decimal number instead.

So much thanks for your feedback, I'll be fixing this soon, if you found something else please let us know. 😉

[pateketrueke]

This is getting complex: mafintosh/is-my-json-valid#172

I'm trying to understand this properly, using this validator: https://json-schema-validator.herokuapp.com/

[ {
  "level" : "error",
  "schema" : {
    "loadingURI" : "#",
    "pointer" : ""
  },
  "instance" : {
    "pointer" : ""
  },
  "domain" : "validation",
  "keyword" : "multipleOf",
  "message" : "remainder of division is not zero (13119267.290000001 / 0.01)",
  "value" : 13119267.290000001,
  "divisor" : 0.01
} ]

The value 13119267.290000001 is not valid, but 0.94 is, of course, multiple of 0.01 right?

It depends on how validators treat this: https://runkit.com/pateketrueke/5b9ef02f3cede20011d5f06f

The results are weird, seriously!

• is-my-json-schema invalidates the long .290000001 remainder
• tv4, ajv and z-schema both invalidates 0.94 as multipleOf: 0.01 ... why?

We'll try to generate an appropriate value for multipleOf as long validators don't get it wrong.

I think rounding up 13119267.290000001 to 13119267.29 is the best choice and it's easier to solve.

Any thoughts?

• @mafintosh (is-my-json-valid)
• @geraintluff / @Bartvds (tv4)
• @zaggino (z-schema)
• @epoberezkin (ajv)

[Jeffersondyj]

Hello，I just found another problem when multipleOf is float

let jsf = require('json-schema-faker');

let schema = {
    "type": "number",
    "multipleOf": 0.01,
    "minimum": 7,
    "maximum": 10
};

jsf.resolve(schema).then(function(sample) {
    console.log(sample);
});

It was expected to be a number between 7 and 10, just like 7.01, or 9.99
but it turn out to be a number between 0 and 3, just like 0.52, 2.88

Then I found the source code: https://github.com/json-schema-faker/json-schema-faker/blob/master/src/lib/types/number.js

line38 to line50, in line50, should return min + num instead of return num

And in this ut, https://github.com/json-schema-faker/json-schema-faker/blob/master/tests/schema/core/issues/issue-252.json
when minimum is zero, the ut will be passed. So maybe we should add a ut when minimum is not zero

Thank you very much for your replying.

[pateketrueke]

Interesting issue, feel free to change the code as you think and submit it as PR!

I'll be checking this as soon as I can, any help is very appreciated.

[GaryStrange]

Hi, was the original issue resolved?

I just ran a schema through the online .org site and it didn't generate fake values that were faithful to my multipleOf definitions.

Thanks,
Gary

[pateketrueke]

Hi @GaryStrange I think it is solved, but you know, there could be regressions.

¿Can you share the schema and output you got? Thank you!

[GaryStrange]

It appears to be non-deterministic so if you have enough 'number' attributes you can increase your chances of exposing the problem.

enter...

{
"QTYORDERED": {
"type": "number",
"multipleOf": 1e-7
},
"QTYORDERED2": {
"type": "number",
"multipleOf": 1e-7
},
"QTYORDERED3": {
"type": "number",
"multipleOf": 1e-7
},
"QTYORDERED4": {
"type": "number",
"multipleOf": 1e-7
},
"QTYORDERED5": {
"type": "number",
"multipleOf": 1e-7
}
}

into

https://json-schema-faker.js.org/

and you should see at least on fake with more than 7 d.p

[pateketrueke]

Woah, you're using 1e-7 as a multiple, do you think is a common case?

[lucas-weje]

Hi,

I am experiencing the same problem as @GaryStrange with the multipleOf definitions.

Currently working with SAP data types, and you can see a snippet of my schema below:

Using jsf.generate() on the schema I am then returned this:

Here you can see 'CDEC31_0' does not conform to the multipleOf = 1.

Hope this makes sense, and that you can help :)

[pateketrueke]

Got it, I think we could spent some time rewriting a simple solution for multipleOf, then integrate it back to JS, what do you think?