MyData

my-data.ts

import {FromSchema} from 'json-schema-to-ts'
import Ajv from 'ajv'

const ajv = new Ajv()

const schema = {
  type: 'object',
  properties: {
    foo: { type: 'integer' },
    bar: { type: 'string' }
  },
  required: [ 'foo' ],
  additionalProperties: false
} as const

// we can derive the literal type directly with typeof because we used "as const" at the end
type MyDataSchema = typeof schema

// this type is exactly what you would expect
type MyData = FromSchema<MyDataSchema>

const validate = ajv.compile<MyData>( schema )

// type as any to mock getting from unknown source
const data: any = {
  foo: 1,
  bar: 'abc'
}

if( validate( data ) ){
  console.log( data.foo )
} else {
  console.log( validate.errors )
}