feat: add user activity search component (#716)

Fixes: #710

src/app/home/home.component.ts

@@ -1,5 +1,11 @@
 /** Angular Imports */
 import { Component, OnInit } from '@angular/core';
+import { FormControl } from '@angular/forms';
+import { Observable } from 'rxjs';
+import { startWith, map } from 'rxjs/operators';
+
+/** Custom Imports. */
+import { activities } from './activities';
 
 /** Custom Services */
 import { AuthenticationService } from '../core/authentication/authentication.service';
@@ -16,18 +22,49 @@ export class HomeComponent implements OnInit {
 
   /** Username of authenticated user. */
   username: string;
+  /** Activity Form. */
+  activityForm: any;
+  /** Search Text. */
+  searchText: FormControl = new FormControl();
+  /** Filtered Activities. */
+  filteredActivities: Observable<any[]>;
+  /** All User Activities. */
+  allActivities: any[] = activities;
 
   /**
    * @param {AuthenticationService} authenticationService Authentication Service.
+   * @param {FormBuilder} formBuilder Form Builder.
    */
   constructor(private authenticationService: AuthenticationService) { }
 
   /**
    * Sets the username of the authenticated user.
+   * Set Form.
    */
   ngOnInit() {
     const credentials = this.authenticationService.getCredentials();
     this.username = credentials.username;
+    this.setFilteredActivities();
+  }
+
+  /**
+   * Sets filtered activities for autocomplete.
+   */
+  setFilteredActivities() {
+    this.filteredActivities = this.searchText.valueChanges
+    .pipe(
+      map((activity: any) => typeof activity === 'string' ? activity : activity.activity),
+      map((activityName: string) => activityName ? this.filterActivity(activityName) : this.allActivities));
+  }
+
+  /**
+   * Filters activities.
+   * @param activityName Activity name to filter activity by.
+   * @returns {any} Filtered activities.
+   */
+  private filterActivity(activityName: string): any {
+    const filterValue = activityName.toLowerCase();
+    return this.allActivities.filter(activity => activity.activity.toLowerCase().indexOf(filterValue) === 0);
   }
 
 }