JavaScriptの標準APIでシンプルな日時をパースする

const parseDatetime = (input) => {
  // 2020-01-01T00:00Z, 2020-01-01T00:00+09:00, 2020-01-01T00:00
  const datetimeRegex = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}(Z|[+-]\d{2}:\d{2})?$/

  const result = input.match(datetimeRegex)

  if (result !== null) {
    const datetime = input + (result[1] ? '' : '+09:00')

    const date = new Date(datetime)

    if (!Number.isNaN(date)) {
      return date
    }
  }

  throw new Error('Invalid datetime')
}