Show announcement validation errors on the frontend

app/controllers/announcement_controller.rb

@@ -23,7 +23,9 @@ class AnnouncementController < ApplicationController
   end
 
   def update
-    if Announcement.update(params[:id], announcement_params)
+    @announcement = Announcement.find(params[:id])
+    @announcement.update(announcement_params)
+    if @announcement.save
       flash[:success] = "Announcement updated successfully."
       redirect_to announcement_index_path
     else

app/views/announcement/edit.html.haml

@@ -1,6 +1,16 @@
 - provide(:title, generate_title("Edit announcement"))
 .container.j2-page
   = bootstrap_form_for(@announcement, url: {action: "update"}, method: "PATCH") do |f|
+    - if @announcement.errors.any?
+      .row
+        .col-md-12
+          .alert.alert-danger
+            %strong
+              = pluralize(@announcement.errors.count, "error")
+              prohibited this announcement from being saved:
+            %ul
+              - @announcement.errors.full_messages.each do |err|
+                %li= err
     .row
       .col-md-12
         = f.text_area :content, label: "Content"

app/views/announcement/new.html.haml

@@ -1,6 +1,16 @@
 - provide(:title, generate_title("Add new announcement"))
 .container.j2-page
   = bootstrap_form_for(@announcement, url: {action: "create"}) do |f|
+    - if @announcement.errors.any?
+    .row
+      .col-md-12
+        .alert.alert-danger
+          %strong
+            = pluralize(@announcement.errors.count, "error")
+            prohibited this announcement from being saved:
+          %ul
+            - @announcement.errors.full_messages.each do |err|
+              %li= err
     .row
       .col-md-12
         = f.text_area :content, label: "Content"