if (window.matchMedia('(max-width: 700px)').matches) {
  for (const linkElement of document.querySelectorAll('.order-project__more-details-btn')) {
    linkElement.setAttribute('href', 'examples-foundation-640')
  }
}

const dateA = new Date('...')
const dateB = new Date('...')

// разница в секундах с точностью до миллисекунды
const differenceInSeconds = (dateA.getTime() - dateB.getTime()) / 1000

// затем можно или отбросить дробную часть
console.log(Math.trunc(differenceInSeconds))
// или округлить одним из методов
console.log(Math.round(differenceInSeconds))

let lastReqDate
app.get('/api/v1/example', (req, res) => {
  const date = new Date()
  let diff
  if (lastReqDate != null) {
    diff = (date.getTime() - lastReqDate.getTime()) / 1000
  }
  if (diff != null && diff < 120) {
      diff = Math.ceil(diff) // округление до ближайшего большего целого
      res.header('Retry-After', diff)
      res.status(429) // Too Many Requests
      res.send({ retryAfter: diff })
  } else {
      lastReqDate = date
      // выполнение запроса разрешено
  }
})

class Lectures extends React.PureComponent {

    state = {
        lectures: null,
        lecturesError: null,
        lecturesPending: true,
    }

    async componentDidMount() {
        await this.fetchLectures()
    }

    async fetchLectures() {
        this.setState({ lectures:null, lecturesError:null, lecturesPending:true })
        try {
            const lectures = (await firebase.database().ref('lectures').once('value')).val()
            console.log(lectures)
            this.setState({ lectures, lecturesError:null, lecturesPending:false })
        } catch (lecturesError) {
            console.error(lecturesError)
            this.setState({ lectures:null, lecturesError, lecturesPending:false })
        }
    }

    render() {
        const { lectures, lecturesError, lecturesPending } = this.state
        return (
            <section>
                <h1>Лекции</h1>
                {lecturesPending && (
                    <div>Загружаются...</div>
                )}
                {lecturesError != null && (
                    <div>Не удалось загрузить: {lecturesError.message}</div>
                )}
                {lectures != null && (
                    <ul>
                        {lectures.map((lecture) => (
                            <li
                                key={lecture.id}
                            >
                                {lecture.name}
                            </li>
                        ))}
                    </ul>
                )}
            </section>
        )
    }
}