const Ajv = require('ajv').default
const ajv = new Ajv()
const ajvKeywords = require('ajv-keywords')
ajvKeywords(ajv)
const stringSchema = {
  type: 'string',
  pattern: 'a'
}
const stringSchema3 = {
  $id: 'regexp',
  type: 'string',
  regexp: {
    pattern: 'a',
    flags: 'i'
  }
}
console.log(ajv.validate(stringSchema, "a")) // true
console.log(ajv.validate(stringSchema3, "A")) // false