Alik auto nick doplnovac

{
    const SEP = ', '

    const input = document.querySelector('#say')
    const getUsers = () => [...document.querySelectorAll('#table-user>li>h4')].map(el => el.innerText)
    const normalize = str => str
      .toLowerCase()
      .normalize("NFD")
      .replace(/[\u0300-\u036f]/g, "")
      .replace('–', '-') // because –MM–

    let prefix = '' // part of user input against which are nicks being matched
    let nickIndex = 0 // currently selected nick

    const autoComplete = (event) => {
        if (event.key !== 'Tab') {
            if (event.key !== 'Shift') {
                nickIndex = 0
                prefix = ''
            }
            return
        }
        event.preventDefault()

        prefix = prefix || normalize(input.value.split(' ').pop())

        const nicks = getUsers().filter(nick => normalize(nick).startsWith(prefix))
        if (nicks.length === 0) { // no match - do nothing
            return
        }
        if (nickIndex >= nicks.length) { // decrease index if someone left since previous call
            nickIndex = nicks.length-1
        }
        const previous = input.value.split(SEP).slice(0,input.value.endsWith(SEP)?-2:-1).join(SEP)
        // when adressing several nicks, `previous` should contain already prefilled nicks
        input.value = (previous && previous + SEP) + nicks[nickIndex] + SEP

        if (!event.shiftKey) { // rotate index forward ...
            nickIndex++
            nickIndex %= nicks.length
        } else { // ... or backwards
            nickIndex--
            nickIndex += nicks.length
            nickIndex %= nicks.length
        }
    }

    input.addEventListener('keydown', autoComplete)
}