Change dimensions middleware to parseParams mw

Related: simcaq/SCRUM#18

src/libs/middlewares/dimensions.js

-/**
-* Dimensions middleware
-*
-* EXAMPLE:
-* Use it with no parameters to get all the dimensions specified
-* app.get('/', dimensions(), function(req, res, next){})
-*
-* Use it with an array of accepted values
-* app.get('/', dimensions(['year', 'location']), function(req, res, next){})
-*
-* Use it globally
-* app.use(dimensions())
-*/
-
-/**
- * This function returns the intersection of two arrays
- * @param  {array} a [description]
- * @param  {array} b [description]
- * @return {array}   [description]
- */
-function intersect(a, b) {
-    let t;
-    if (b.length > a.length) {
-        t = b; b = a; a = t;
-    }
-    return a.filter((e) => b.indexOf(e) !== -1);
-}
-
-function dimensions(dims) {
-    return (req, res, next) => {
-        req.dims = {};
-        if (req.query.dims) {
-            const params = req.query.dims.split(',');
-            const dimObj = {};
-            for (const param of params) {
-                const kv = param.split(':');
-                dimObj[kv[0]] = (typeof kv[1] === 'undefined') ? null : kv[1];
-            }
-            // for(let i=0; i<params.length; ++i) {
-            //     let kv = params[i].split(':');
-            //     dimObj[kv[0]] = (typeof kv[1] === 'undefined') ? null : kv[1];
-            // }
-
-            // If the dims array exists and is not empty
-            if (typeof dims !== 'undefined' && dims.length > 0) {
-                const intersection = intersect(dims, Object.keys(dimObj));
-                for (let i = 0; i < intersection.length; ++i) {
-                    req.dims[intersection[i]] = dimObj[intersection[i]];
-                }
-            } else {
-                req.dims = dimObj;
-            }
-        }
-        next();
-    };
-}
-
-module.exports = dimensions;

src/libs/middlewares/parseParams.js

+/**
+* ParseParams middleware
+*
+* EXAMPLE:
+* Use it with no parameters to get all the params specified
+* app.get('/', parseParams('dims'), function(req, res, next){})
+*
+* Use it with an array of accepted values
+* app.get('/', parseParams('filter', ['year', 'location']), function(req, res, next){})
+*
+* Use it globally
+* app.use(parseParams('dims'))
+*/
+
+const libs = `${process.cwd()}/libs`;
+
+const log = require(`${libs}/log`)(module);
+
+ // This function returns the intersection of two arrays
+function intersect(a, b) {
+    let t;
+    if (b.length > a.length) {
+        t = b; b = a; a = t;
+    }
+    return a.filter((e) => b.indexOf(e) !== -1);
+}
+
+function parseParams(queryParam, arr) {
+    return (req, res, next) => {
+        req[queryParam] = {};
+        if (req.query[queryParam]) {
+            const params = req.query[queryParam].split(',');
+            // Temporary object to hold the params and it's values
+            const obj = {};
+            for (const param of params) {
+                // Get the key and the value - state:41 is key 'state' whith value 41
+                const kv = param.split(':');
+                // Check if there is a value. If there isn't, assign null
+                obj[kv[0]] = (typeof kv[1] === 'undefined') ? null : kv[1];
+            }
+
+            // If the array exists and is not empty we intersect
+            if (typeof arr !== 'undefined' && arr.length > 0) {
+                // Intersect the keys of the obj with the array arr.
+                // The intersection array is assigned with the keys
+                const intersection = intersect(arr, Object.keys(obj));
+                // This is a bit tricky...
+                // For each key in the intersection array we get it's value in the obj
+                // and assign it to the custom attribute in the req obj.
+                // For example: instersection => ["state"] so
+                // obj[intersection[i]] (with i=0) is obj["state"], that is 41
+                // and req[queryParam]["state"] = 41
+                for (let i = 0; i < intersection.length; ++i) {
+                    req[queryParam][intersection[i]] = obj[intersection[i]];
+                }
+            } else {
+                req[queryParam] = obj;
+            }
+        }
+        next();
+    };
+}
+
+module.exports = parseParams;