Detailed explanation of Angular structural directive modules and styles

<ng-template [ngIf]="item.reminder">
      <mat-icon>
        alarm
      </mat-icon>
    </ng-template>
    
    <!-- <mat-icon *ngIf="item.reminder">
      alarm
    </mat-icon> -->

constructor(guard: any, router: Router);
    /**
     * Creates a module with all the router providers and directives. It also optionally sets up an
     * application listener to perform an initial navigation.
     *
     * Options (see `ExtraOptions`):
     * * `enableTracing` makes the router log all its internal events to the console.
     * * `useHash` enables the location strategy that uses the URL fragment instead of the history
     * API.
     * * `initialNavigation` disables the initial navigation.
     * * `errorHandler` provides a custom error handler.
     * * `preloadingStrategy` configures a preloading strategy (see `PreloadAllModules`).
     * * `onSameUrlNavigation` configures how the router handles navigation to the current URL. See
     * `ExtraOptions` for more details.
     * * `paramsInheritanceStrategy` defines how the router merges params, data and resolved data
     * from parent to child routes.
     */
    static forRoot(routes: Routes, config?: ExtraOptions): ModuleWithProviders<RouterModule>;
    /**
     * Creates a module with all the router directives and a provider registering routes.
     */
    static forChild(routes: Routes): ModuleWithProviders<RouterModule>;
}

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';

@NgModule({
  declarations: [],
  imports: [
    CommonModule
  ]
})
export class ServicesModule { }

import { NgModule, ModuleWithProviders } from '@angular/core';
import { CommonModule } from '@angular/common';

@NgModule()
export class ServicesModule { 
  static forRoot():ModuleWithProviders{
    return {
      ngModule: ServicesModule,
      providers:[]
    }
  }
}

<mat-list-item class="container" [@item]="widerPriority" [ngClass]="{
  'priority-normal':item.priority===3,
  'priority-important':item.priority===2,
  'priority-emergency':item.priority===1
}"

<div class="content" mat-line [class.completed]="item.completed">
    <span [matTooltip]="item.desc">{{item.desc}}</span>
</div>

<app-task-list *ngFor="let list of lists" 
  class="list-container"
  app-droppable="true"
  [dropTags]="['task-item','task-list']"
  [dragEnterClass]="'drag-enter'"
  [app-draggable]="true"
  [dragTag]="'task-list'"
  [draggedClass]="'drag-start'"
  [dragData]="list"
  (dropped)="handleMove($event,list)"
  [ngStyle]="{'order': list.order}"
  >

lists = [
    {
      id: 1,
      name: "To Do",
      order: 1,
      tasks:
        {
          id: 1,
          desc: "Task 1: Go to Starbucks to buy coffee",
          completed: true,
          priority: 3,
          owner:
            id: 1,
            name: "Zhang San",
            avatar: "avatars:svg-11"
          },
          dueDate: new Date(),
          reminder: new Date()
        },
        {
          id: 2,
          desc: "Task 1: Complete the PPT assignment assigned by the boss",
          completed: false,
          priority: 2,
          owner:
            id: 2,
            name: "Li Si",
            avatar: "avatars:svg-12"
          },
          dueDate: new Date()
        }
      ]
    },
    {
      id: 2,
      name: "In Progress",
      order:2,
      tasks:
        {
          id: 1,
          desc: "Task 3: Project Code Review",
          completed: false,
          priority: 1,
          owner:
            id: 1,
            name: "Wang Wu",
            avatar: "avatars:svg-13"
          },
          dueDate: new Date()
        },
        {
          id: 2,
          desc: "Task 1: Develop a project plan",
          completed: false,
          priority: 2,
          owner:
            id: 2,
            name: "Li Si",
            avatar: "avatars:svg-12"
          },
          dueDate: new Date()
        }
      ]
    }
  ];

handleMove(srcData,targetList){
    switch (srcData.tag) {
      case 'task-item':
        console.log('handling item');
        break;
      case 'task-list':
        console.log('handling list');
        const srcList = srcData.data;
        const tempOrder = srcList.order;
        srcList.order = targetList.order;
        targetList.order = tempOrder;
      default:
        break;
    }
  }