115 lines
3.5 KiB
JavaScript
115 lines
3.5 KiB
JavaScript
"use strict";
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// Node.js pagination middleware and view helpers.
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// * Author: [@niftylettuce](https://twitter.com/#!/niftylettuce)
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// * Source: <https://github.com/niftylettuce/middleware paginate>
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const qs = require("qs");
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const url = require("url");
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const _ = require("lodash");
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//const util = require('util');
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const href = (req) => {
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return function (prev, params) {
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let query = _.clone(req.query);
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if (typeof prev === "object") {
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params = prev;
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prev = false;
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} else {
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prev = typeof prev === "boolean" ? prev : false;
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query.page = parseInt(query.page, 10);
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query.page = prev ? (query.page -= 1) : (query.page += 1);
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query.page = query.page < 1 ? 1 : query.page;
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}
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// allow overriding querystring params
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// (useful for sorting and filtering)
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// another alias for `_.assign` is `_.extend`
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if (_.isObject(params)) query = _.assign(query, params);
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return url.parse(req.originalUrl).pathname + "?" + qs.stringify(query);
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};
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};
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const hasNextPages = (req) => {
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return function (pageCount) {
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if (typeof pageCount !== "number" || pageCount < 0)
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throw new Error("middleware paginate: `pageCount` is not a number >= 0");
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return req.query.page < pageCount;
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};
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};
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const getArrayPages = (req) => {
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return function (limit, pageCount, currentPage) {
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const maxPage = pageCount;
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// limit default is 3
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limit = limit || 3;
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if (typeof limit !== "number" || limit < 0) throw new Error("middleware paginate: `limit` is not a number >= 0");
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if (typeof pageCount !== "number" || pageCount < 0)
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throw new Error("middleware paginate: `pageCount` is not a number >= 0");
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currentPage = parseInt(currentPage, 10);
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if (Number.isNaN(currentPage) || currentPage < 0)
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throw new Error("middleware paginate: `currentPage` is not a number >= 0");
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if (limit > 0) {
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let end = Math.min(Math.max(currentPage + Math.floor(limit / 2), limit), pageCount);
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let start = Math.max(1, currentPage < limit - 1 ? 1 : end - limit + 1);
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let pages = [];
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for (let i = start; i <= end; i++) {
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pages.push({
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number: i,
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url: href(req)().replace("page=" + (currentPage + 1), "page=" + i),
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});
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}
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return pages;
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}
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};
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};
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const middleware = (limit = 10, maxLimit = 50) => {
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const _limit = typeof limit === "number" ? parseInt(limit, 10) : 10;
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const _maxLimit = typeof maxLimit === "number" ? parseInt(maxLimit, 10) : 50;
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return function _middleware(req, res, next) {
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req.query.page = typeof req.query.page === "string" ? parseInt(req.query.page, 10) || 1 : 1;
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req.query.limit = typeof req.query.limit === "string" ? parseInt(req.query.limit, 10) || 0 : _limit;
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if (req.query.limit > _maxLimit) req.query.limit = _maxLimit;
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if (req.query.page < 1) req.query.page = 1;
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if (req.query.limit < 0) req.query.limit = 0;
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//req.skip = req.offset = (req.query.page * req.query.limit) - req.query.limit;
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res.locals.paginate = res.locals.paginate ? res.locals.paginate : {};
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res.locals.paginate.page = req.query.page;
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res.locals.paginate.limit = req.query.limit;
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res.locals.paginate.href = href(req);
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res.locals.paginate.hasPreviousPages = req.query.page > 1;
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res.locals.paginate.hasNextPages = hasNextPages(req);
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res.locals.paginate.getArrayPages = getArrayPages(req);
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// Todo lo relativo a paginación va ahora a res.locals.paginate
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delete req.query.page;
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delete req.query.limit;
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next();
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};
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};
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module.exports = {
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href,
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hasNextPages,
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getArrayPages,
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middleware,
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};
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