67 lines
2.2 KiB
JavaScript
67 lines
2.2 KiB
JavaScript
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"use strict";
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/*
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Sort middleware
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This module exports a function that takes a configuration object parameter with the following
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properties:
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{
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validKeys: Array of strings (case sensitive),
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default: String (optional, by default assigned to the first element of the
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validKeys array with ascending sorting order unless prefixed by a "-")
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}
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and returns an express compatible middleware function (req, res, next) that parses the following
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parameters from the req.query object and sets an object on the res.locals.sort having the following
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properties:
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Object - with keys for the sort value fields and value a boolean denoting ascending order
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or not
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*/
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const middleware = (config) => {
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if (typeof config !== "object" || config === null) {
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throw new Error("The config parameter is mandatory and should be an object!");
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}
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config = config || {};
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if (!config.default && (!Array.isArray(config.validKeys) || config.validKeys.length === 0)) {
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throw new Error("config.validKeys should be a non empty array of strings or a config.default key should be defined!");
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}
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config.default = config.default || config.validKeys[0];
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const defaultSortIsAscending = config.default.substring(0, 1) !== "-";
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return function (req, res, next) {
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const sortKeys = Array.isArray(req.query.sort)
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? req.query.sort
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: req.query.sort
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? [req.query.sort]
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: [];
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const sortObject = sortKeys.reduce(function (c, key) {
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const ascending = key.substring(0, 1) !== "-";
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if (!ascending) {
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key = key.substr(1);
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}
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if (key && config.validKeys && config.validKeys.indexOf(key) !== -1 ) {
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c[key] = ascending;
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}
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return c;
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}, {});
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if (Object.keys(sortObject).length === 0) {
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sortObject[
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defaultSortIsAscending
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? config.default
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: config.default.substr(1)
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] = defaultSortIsAscending;
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}
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res.locals.sort = sortObject;
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next();
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};
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}
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module.exports = {
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middleware
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}
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