implemented removal of required task

frontend/src/routes/task/RequiredTasks.svelte

@@ -22,20 +22,14 @@
             error = null;
             let newTask = await resp.json();
             if (newTask.project_id != task.project_id){
-                alert('prject mismatch!');
+                alert('project mismatch!');
                 return;
             }
             task.required_tasks_ids.push(new_task_id);
             requiredTasks[new_task_id] = newTask;
-            url = api(`task/${task.id}`);
-            resp = await fetch(url,{
-                credentials : 'include',
-                method      : 'PATCH',
-                body        : JSON.stringify({required_tasks_ids:task.required_tasks_ids})
-            });
+            await patch();
             delete candidates[new_task_id];
-        }
-        if (!resp.ok) {
+        } else {
             error = await resp.text();
         }
     }
@@ -90,6 +84,24 @@
         return false;
     }
 
+    async function patch(){
+            const url  = api(`task/${task.id}`);
+            const resp = await fetch(url,{
+                credentials : 'include',
+                method      : 'PATCH',
+                body        : JSON.stringify({required_tasks_ids:task.required_tasks_ids})
+            });
+            if (!resp.ok){
+                error = await resp.text();
+            }
+    }
+
+    async function unlink(required_task){
+        task.required_tasks_ids = task.required_tasks_ids.filter(item => item != required_task.id);
+        patch();
+        delete requiredTasks[required_task.id];
+    }
+
     onMount(loadTasks);
 </script>
 
@@ -97,7 +109,7 @@
 <ul class="required task list">
     {#each Object.values(requiredTasks) as task}
     <li class="task" >
-        <a href="/task/{task.id}/view" onclick={openTask} >{task.name}</a>
+        <a href="/task/{task.id}/view" onclick={openTask} >{task.name}</a>&nbsp;<button onclick={() => unlink(task)} class="symbol"></button>
     </li>
     {/each}
 </ul>