ajv.addKeyword({
  keyword: "range",
  type: "number",
  schemaType: "array",
  implements: "exclusiveRange",
  compile: ([min, max], parentSchema) =>
    parentSchema.exclusiveRange === true
      ? (data) => data > min && data < max
      : (data) => data >= min && data <= max,
})

const schema = {range: [2, 4], exclusiveRange: true}
const validate = ajv.compile(schema)
console.log(validate(2.01)) // true
console.log(validate(3.99)) // true
console.log(validate(2)) // false
console.log(validate(4)) // false

ajv.addKeyword({
  keyword: "constant",
  validate: (schema, data) =>
    typeof schema == "object" && schema !== null ? deepEqual(schema, data) : schema === data,
  errors: false,
})

const schema = {
  constant: 2,
}
const validate = ajv.compile(schema)
console.log(validate(2)) // true
console.log(validate(3)) // false

const schema = {
  constant: {foo: "bar"},
}
const validate = ajv.compile(schema)
console.log(validate({foo: "bar"})) // true
console.log(validate({foo: "baz"})) // false

async function test() {
  
  //...
const schema = JSON.parse(await fs.readFile("./schema/buttplug-schema.json", "utf-8"));
  const validator = new ajv();
  validator.addMetaSchema(require("ajv/lib/refs/json-schema-draft-06.json"));
  const jsonValidator = validator.compile(schema);
  
  //...
}

const ajv = new Ajv()

ajv.addKeyword({
  keyword: "idExists",
  async: true,
  type: "number",
  validate: checkIdExists,
})

async function checkIdExists(schema, data) {
  // this is just an example, you would want to avoid SQL injection in your code
  const rows = await sql(`SELECT id FROM ${schema.table} WHERE id = ${data}`)
  return !!rows.length // true if record is found
}

const schema = {
  $async: true,
  properties: {
    userId: {
      type: "integer",
      idExists: {table: "users"},
    },
    postId: {
      type: "integer",
      idExists: {table: "posts"},
    },
  },
}

const validate = ajv.compile(schema)

validate({userId: 1, postId: 19})
  .then(function (data) {
    console.log("Data is valid", data) // { userId: 1, postId: 19 }
  })
  .catch(function (err) {
    if (!(err instanceof Ajv.ValidationError)) throw err
    // data is invalid
    console.log("Validation errors:", err.errors)
  })

const ajv = new Ajv()
const validate = ajv.addSchema(defsSchema).compile(schema)