refactor checked function

server.js

@@ -118,59 +118,49 @@ if (env === 'production' && useHttps === 'true') {
   app.use(utils.forceHttps)
 }
 
-if (useAutoStoreData === 'true') {
-  app.use(utils.autoStoreData)
+// add nunjucks function called 'checked' to populate radios and checkboxes,
+// needs to be here as it needs access to req.session and nunjucks environment
+var addCheckedFunction = function (app, nunjucksEnv) {
   app.use(function (req, res, next) {
-    // add nunjucks function to get values, needs to be here as they need access to req.session
-
-    nunjucksAppEnv.addGlobal('checked', function (name, value) {
+    nunjucksEnv.addGlobal('checked', function (name, value) {
+      // check session data exists
       if (req.session.data === undefined) {
         return ''
       }
 
       var storedValue = req.session.data[name]
 
+      // check the requested data exists
       if (storedValue === undefined) {
         return ''
       }
 
-      if (Array.isArray(storedValue)) {
-        var inArray = storedValue.indexOf(value) !== -1
-        return inArray ? 'checked' : ''
-      } else {
-        return value === storedValue ? 'checked' : ''
-      }
-    })
-
-    next()
-  })
-
-  documentationApp.use(function (req, res, next) {
-    // add nunjucks function to get values, needs to be here as they need access to req.session
-
-    nunjucksDocumentationEnv.addGlobal('checked', function (name, value) {
-      if (req.session.data === undefined) {
-        return ''
-      }
-
-      var storedValue = req.session.data[name]
-
-      if (storedValue === undefined) {
-        return ''
-      }
+      var checked = ''
 
+      // if data is an array, check it exists in the array
       if (Array.isArray(storedValue)) {
-        var inArray = storedValue.indexOf(value) !== -1
-        return inArray ? 'checked' : ''
+        if (storedValue.indexOf(value) !== -1) {
+          checked = 'checked'
+        }
       } else {
-        return value === storedValue ? 'checked' : ''
+        // the data is just a simple value, check it matches
+        if (storedValue === value) {
+          checked = 'checked'
+        }
       }
+      return checked
     })
 
     next()
   })
 }
 
+if (useAutoStoreData === 'true') {
+  app.use(utils.autoStoreData)
+  addCheckedFunction(app, nunjucksAppEnv)
+  addCheckedFunction(documentationApp, nunjucksDocumentationEnv)
+}
+
 // Disallow search index idexing
 app.use(function (req, res, next) {
   // Setting headers stops pages being indexed even if indexed pages link to them.