TypeScript Issue with JTDSchema and Elements Properties

When trying to specify a simple schema with an array of strings TypeScript produces a TypeScript compilation error. The same schema run in plain javascript works correctly.

What version of Ajv are you using? Does the issue happen if you use the latest version?

Ajv 8.6.2

TypeScript 4.3.5

Ajv options object

import Ajv, { JTDSchemaType } from 'ajv/dist/jtd'

const ajv = new Ajv()

JSON Schema

interface Schema {
  x: Date
  y: [string]
}

const schema: JTDSchemaType<Schema> = {
  properties: {
    x: { type: 'timestamp' },
    y: {
      elements: { type: 'string' }
    }
  }
}

Your code

import Ajv, { JTDSchemaType } from 'ajv/dist/jtd'

const ajv = new Ajv()

interface Schema {
  x: Date
  y: [string]
}

const schema: JTDSchemaType<Schema> = {
  properties: {
    x: { type: 'timestamp' },
    y: {
      elements: { type: 'string' }
    }
  }
}

ajv.compile(schema)

[AndrewBarba]

Oh man. I’m sorry. Coming from Swift…

[epoberezkin]

JTD catches type errors 😉