json-schema-fast-check

JSON Schema is a useful way to define input and output schemas.

Property testing is a useful way to make sure that a function behaves as expected with any valid input.

json-schema-fast-check implements arbitrary JSON Schema values using the fast-check library for property testing.

Example

``typescript
import jsfc from "json-schema-fast-check";
import fc from "fast-check";

const getAge = (data: any) =>
typeof data === "object" && typeof data.age === "number"
? Math.floor(data.age)
: null;

const userSchema = {
type: "object",
properties: {
required: ["name", "id"],
name: {
type: "string"
},
age: {
type: "integer",
minimum: 0
},
id: {
type: "integer"
}
}
}

test("my function yields positive age or null", () => {
fc.assert(fc.property(jsfc(userSchema), user => {
const age = getAge(user);
return age === null || age >= 0;
}));
});
`

API

The API has only two functions - the default one (which we call jsfc just cuz) and a helper function called generate.

$3

`typescript
const arbitrary = jsfc(mySchema);
`

Creates a fast-check arbitrary from valid JSON schema.

$3

`typescript
const json = generate(mySchema);
`

Generates a single valid JSON object that conforms to the schema.

A note on JSON Schema

The actual schema used here is not JSON Schema but rather a subset of JSON Schema called "The Subest of JSON Schema I Was Not Too Lazy To Define." I also added some faker-js sugar (see the tests).

Todo

There is plenty of stuff that is not implemented yet. I'd really appreciate your help!

* minProperties and maxProperties for objects
* additionalItems for arrays
* tuples bigger than length 16
* if/then/else syntax
* proper use of oneOf
* use objects as dependencies` as well as arrays