Pagination Algorithm

pagination.js

pagination(currentPage, pageCount) {
    let delta = 1,
        left = currentPage - delta,
        right = currentPage + delta + 1,
        result = []

    result = Array.from({ length: pageCount }, (v, k) => k + 1)
        .filter(i => i && i >= left && i < right)

    if (result.length > 1) {
        // Add first page and dots
        if (result[0] > 1) {
            if (result[0] > 2) {
                // Add dots
                result.unshift('...')
            }
            // Add first page
            result.unshift(1)
        }

        // Add dots and last page
        if (result[result.length - 1] < pageCount) {
            if (result[result.length - 1] !== pageCount - 1) {
                // Add dots
                result.push('...')
            }
            // Add last page
            result.push(pageCount)
        }
    }

    return result
}