paginate.html

<script>
    let currentPage = 0;
    const pagesCount = 15;

    document.addEventListener('contextmenu', function(ev) {
        ev.preventDefault();
        if (currentPage > 1) {
            currentPage--;
        }
        generatePageButtons(currentPage, pagesCount)
        return false;
    }, false);


    document.addEventListener('click', function(ev) {
        ev.preventDefault();
        if (currentPage < pagesCount) {
            currentPage++;
        }
        generatePageButtons(currentPage, pagesCount)
        return false;
    }, false);


    function generatePageButtons(
        currentPage,
        pagesCount,
        startCount = 3,
        middleCount = 2,
        endCount = 3,
        strSplit = '...'
    ) {

        let pageBtns = [
            ...Array.from(new Array(startCount), (x, i) => i + 1),
            ...Array.from(new Array(1 + middleCount * 2), (x, i) => i + currentPage - middleCount),
            ...Array.from(new Array(endCount), (x, i) => i + pagesCount - endCount + 1),
        ].reduce( (acc, val) => {
            if (val < 1 || val > pagesCount || acc.indexOf(val) !== -1) return acc;
            if (val - acc[acc.length - 1] > 1) {
                //acc.push(strSplit);
                acc.push((val - acc[acc.length - 1] == 2) ? val - 1 : strSplit);
            }
            acc.push(val);
            return acc;
        }, []);

        console.log(pageBtns);
    }

</script>