clean up error handling

.prettierrc

@@ -0,0 +1,7 @@
+{
+  "printWidth": 80,
+  "semi": false,
+  "singleQuote": true,
+  "trailingComma": "es5",
+  "arrowParens": "always"
+}

cypress/plugins/index.js

@@ -1,43 +1,31 @@
-const { join } = require("path");
-const knexFactory = require("knex");
+const { join } = require('path')
+const knexFactory = require('knex')
 
 module.exports = (on, config) => {
   // `on` is used to hook into various events Cypress emits
   // `config` is the resolved Cypress config
-  on("task", {
-    deleteAllArticles() {
+  on('task', {
+    deleteAllArticles () {
+      const filename = join(__dirname, '..', '..', 'server', '.tmp.db')
       const knex = knexFactory({
-        client: "sqlite3",
+        client: 'sqlite3',
         connection: {
-          filename: join(__dirname, "..", "..", "server", ".tmp.db")
+          filename
         },
         useNullAsDefault: true
-      });
+      })
+      // if we are trying to truncate a non-existing table
+      // that is ok - the server API will create them
+      const onError = err =>
+        err.toString().includes('no such table') ? null : Promise.reject(err)
+
+      // truncates all tables created by previous tests
+      // or manually by using the application
       return Promise.all([
-        knex
-          .truncate("Articles")
-          .catch(err =>
-            err.toString().includes("no such table")
-              ? undefined
-              : Promise.reject(err)
-          ),
-        knex
-          .truncate("ArticleTags")
-          .catch(err =>
-            err.toString().includes("no such table")
-              ? undefined
-              : Promise.reject(err)
-          ),
-        ,
-        knex
-          .truncate("Comments")
-          .catch(err =>
-            err.toString().includes("no such table")
-              ? undefined
-              : Promise.reject(err)
-          )
-      ]);
-    },
-    registerNewUserIfNeeded() {}
-  });
-};
+        knex.truncate('Articles').catch(onError),
+        knex.truncate('ArticleTags').catch(onError),
+        knex.truncate('Comments').catch(onError)
+      ])
+    }
+  })
+}