Use strict check of typescript compiler.

1 files changed, 8 insertions, 3 deletions

diff --git a/Timeline/ClientApp/src/app/todo/todo-item/todo-item.component.ts b/Timeline/ClientApp/src/app/todo/todo-item/todo-item.component.ts
index 2ea6997a..50829769 100644
--- a/Timeline/ClientApp/src/app/todo/todo-item/todo-item.component.ts
+++ b/Timeline/ClientApp/src/app/todo/todo-item/todo-item.component.ts
@@ -1,13 +1,18 @@
-import { Component, Input } from '@angular/core';
+import { Component, Input, OnInit } from '@angular/core';
+
 import { TodoItem } from '../todo-item';
+import { throwIfFalsy } from 'src/app/utilities/language-untilities';
 
 @Component({
   selector: 'app-todo-item',
   templateUrl: './todo-item.component.html',
   styleUrls: ['./todo-item.component.css', '../todo-list-color-block.css']
 })
-export class TodoItemComponent {
+export class TodoItemComponent implements OnInit {
 
-  @Input() item: TodoItem;
+  @Input() item: TodoItem | undefined;
 
+  ngOnInit() {
+    throwIfFalsy(this.item, 'item');
+  }
 }