+ queryValue middleware for working with query string

src/middlewares/queryValue.js

@@ -0,0 +1,35 @@
+let contains = (list, i) => list.indexOf(i) > -1;
+
+export function queryValue(params) {
+    let keys = Object.keys(params);
+
+    return async (ctx, next) => {
+        let query = ctx.request.query;
+        ctx.request.query = Object.keys(query)
+            .reduce((q, i) => {
+                if(contains(keys, i)){
+                    let fn = params[i];
+                    q[i] = fn(q[i]);
+                }
+                return q;
+            }, query);
+
+        await next();
+    };
+}
+
+export function booleanify(){
+    return function(value){
+        if(value == 'true') return true;
+        if(value == '1') return true;
+        if(value == 'false') return false;
+        if(value == '0') return false;
+        return Boolean(value);   
+    }
+}
+
+export function arrayify(sep){
+    return function(value){
+        return value.split(sep);
+    }
+}