自訂Pipe使用，使用 ng generate pipe [管道名稱]

本範例使用自訂Orderby排序

src/app/app.component.html

@@ -1 +1 @@
-UTC時間：{{ now | date: "long":"+0800" }}
+<app-task *ngFor="let task of tasks | orderBy: 'State'" [task]="task"></app-task>

src/app/app.component.ts

@@ -1,10 +1,17 @@
 import { Component } from '@angular/core';
 
+import { Task } from './task';
+
 @Component({
   selector: 'my-app',
   templateUrl: './app.component.html',
-  styleUrls: ['./app.component.css'],
+  styleUrls: [ './app.component.css' ]
 })
-export class AppComponent {
-  now = new Date();
+export class AppComponent  {
+  tasks: Task[] = [
+    new Task({ TaskSn: '001', TaskName: '待辦事項 A', State: 'Finish' }),
+    new Task({ TaskSn: '002', TaskName: '待辦事項 B', State: 'Doing' }),
+    new Task({ TaskSn: '003', TaskName: '待辦事項 C', State: 'None' }),
+    new Task({ TaskSn: '004', TaskName: '待辦事項 D', State: 'None' }),
+  ];
 }

src/app/app.module.ts

@@ -4,10 +4,11 @@ import { FormsModule } from '@angular/forms';
 
 import { AppComponent } from './app.component';
 import { TaskComponent } from './task/task.component';
+import { OrderByPipe } from './order-by.pipe';
 
 @NgModule({
   imports:      [ BrowserModule, FormsModule ],
-  declarations: [ AppComponent, TaskComponent ],
+  declarations: [ AppComponent, TaskComponent, OrderByPipe ],
   bootstrap:    [ AppComponent ]
 })
 export class AppModule { }

src/app/order-by.pipe.ts

@@ -0,0 +1,14 @@
+import { Pipe, PipeTransform } from '@angular/core';
+
+@Pipe({
+  name: 'orderBy'
+})
+export class OrderByPipe implements PipeTransform {
+
+  transform(list: any[], prop: string): any[] {
+    return list.sort((a, b) => a[prop] >b[prop]
+    ?1
+    :a[prop]=== b[prop] ?0: -1)
+  }
+
+}