Pagination with dots

pagination.js

function getPages(maxPages, currentPage) {
  let pages = [];

  for (let i = 1; i <= maxPages; i++) {
    if (i === 1 || i === maxPages ||
        (currentPage < 4 && i <= 4) ||
        (i >= currentPage - 1 && i <= currentPage + 1) ||
        (maxPages - currentPage < 3 && maxPages - i <= 3)) {
      pages.push(i);
    } else if (pages[pages.length - 1] !== '...') {
      pages.push('...');
    }
  }

  return pages;
}

console.log(JSON.stringify(getPages(10, 1)));   // [1,2,3,4,"...",10]
console.log(JSON.stringify(getPages(10, 2)));   // [1,2,3,4,"...",10]
console.log(JSON.stringify(getPages(10, 3)));   // [1,2,3,4,"...",10]
console.log(JSON.stringify(getPages(10, 4)));   // [1,"...",3,4,5,"...",10]
console.log(JSON.stringify(getPages(10, 5)));   // [1,"...",4,5,6,"...",10]
console.log(JSON.stringify(getPages(10, 6)));   // [1,"...",5,6,7,"...",10]
console.log(JSON.stringify(getPages(10, 7)));   // [1,"...",6,7,8,"...",10]
console.log(JSON.stringify(getPages(10, 8)));   // [1,"...",7,8,9,10]
console.log(JSON.stringify(getPages(10, 9)));   // [1,"...",7,8,9,10]
console.log(JSON.stringify(getPages(10, 10)));  // [1,"...",7,8,9,10]