Adding pagination to knex.js

knex-pagination.js

module.exports = function(dbConfig) {
	var knex = require('knex')(dbConfig);

	var KnexQueryBuilder = require('knex/lib/query/builder');

	KnexQueryBuilder.prototype.paginate = function (per_page, current_page) {
		var pagination = {};
		var per_page = per_page || 10;
		var page = current_page || 1;
		if (page < 1) page = 1;
		var offset = (page - 1) * per_page;
		return Promise.all([
				this.clone().count('* as count').first(),
				this.offset(offset).limit(per_page)
			])
			.then(([total, rows]) => {
				var count = total.count;
				var rows = rows;
				pagination.total = count;
				pagination.per_page = per_page;
				pagination.offset = offset;
				pagination.to = offset + rows.length;
				pagination.last_page = Math.ceil(count / per_page);
				pagination.current_page = page;
				pagination.from = offset;
				pagination.data = rows;
				return pagination;
			});
	};

	knex.queryBuilder = function () {
		return new KnexQueryBuilder(knex.client);
	};

	return knex;
}

Place it inside whenever folder name u want, in my case, under util folder
util / search.js

class Search {
constructor(query, queryString) {
this.query = query;
this.queryString = queryString;
this.tableName = this.query.and._single.table;
}
pagination(resPerPage) {
let { queryString, query, tableName } = this;

let { page } = queryString;
if (page < 1) page = 1;
let offset = (page - 1) * resPerPage;

query
  .select("name", "price", "description", "ratings", "stock")
  .from(`${tableName}`)
  .offset(offset)
  .limit(resPerPage);

return this;

}
}

module.exports = SearchQuery;

on the other part:
// under the controller folder, create a file. "in my case, it is product.js"

const query = require("../config/database/database"); // this is came from knex configuration
const SearchQuery = require("../utils/searchQuery");

exports.getProducts = catchAsyncErrors(async (req, res, next) => {
const resPerPage = 5;
const search = new SearchQuery(query("products"), req.query)
.pagination(resPerPage);

const products = await search.query;
res.status(200).json({
success: true,
products,
});
});

this is working. kindly see screenshot below.