Pern Stack pagination middleware

 module.exports = (table, _max_limits) => { // global variable let queryString = `select * from ${table}` let arr = [] let results = {} find(queryString) .then((data) => arr = data) .catch(err => res.status(400).json({ err })) return (req, res, next) => { // like convention const { page, limit } = req.query // user input const intPage = parseInt(page, 10) || 1 const intLimit = parseInt(limit, 10) // control user limit const intCtrLimit = intLimit > _max_limits ? _max_limits : intLimit // user limit > _max_limits // algorithms let totals = arr.length let numberOfPages = Math.round(((totals) / intCtrLimit)) let startIndex = (intPage - 1) * intCtrLimit let endIndex = ((intPage * intCtrLimit) - 1) // output let prevPage = (intPage > 0 && intPage <= numberOfPages) ? intPage - 1 : 1 let nexPage = (intPage < numberOfPages) ? intPage + 1 : numberOfPages // not equals but is add one // errors gestion if (intPage <= numberOfPages) { if (intPage > 0) { results = { log: `result of request : page=${intPage} & limit=${intCtrLimit} `, totals, prevPage, nexPage, numberOfPages, limit: intCtrLimit, startIndex, endIndex: endIndex + 1 // like array slice  } } } // like user paigination let paginateDatas = arr.slice(results?.startIndex, results?.endIndex) results.datas = paginateDatas // like middleware principe req.paginateResults = results next() } }