fix(search): improve search: loading indication and other hints

closes #366 (PR #456)

src/app/core/ui/search/search.component.html

@@ -1,26 +1,91 @@
-<div fxHide.xs="true" fxHide="false">
-  <mat-form-field fxFill class="search-field">
-    <span matPrefix><mat-icon class="search-icon" fontIcon="fa-search"></mat-icon>&nbsp;</span>
-    <input matInput (input)="search()" title="Search" [matAutocomplete]="autoResults" [(ngModel)]="searchText">
+<div class="desktop-search-bar" fxHide.xs="true" fxHide="false">
+  <mat-form-field fxFill class="search-field" floatLabel="never">
+    <span matPrefix>
+      <mat-icon matPrefix class="search-icon" fontIcon="fa-search"></mat-icon>
+    </span>
+    <mat-label>Search</mat-label>
+    <input
+      matInput
+      title="Search"
+      [matAutocomplete]="autoResults"
+      [(ngModel)]="searchText"
+      (ngModelChange)="searchStringChanged.next($event)"
+      #searchInput
+    />
   </mat-form-field>
 
-  <mat-autocomplete #autoResults="matAutocomplete" (optionSelected)="clickOption($event.option)">
-    <mat-option *ngFor="let res of results" [value]="''">
-      <app-child-block *ngIf="res.getType()==='Child'" [entity]="res" [ngClass]="{'result-inactive': !res.isActive()}"></app-child-block>
-      <app-school-block *ngIf="res.getType()==='School'" [entity]="res"></app-school-block>
+  <mat-autocomplete
+    #autoResults="matAutocomplete"
+    (optionSelected)="clickOption($event.option)"
+  >
+    <mat-option
+      class="result-hint"
+      *ngIf="
+        searchInput.value.length > 0 &&
+        searchInput.value.length < MIN_CHARACTERS_FOR_SEARCH
+      "
+    >
+      <p>Insert at least {{ MIN_CHARACTERS_FOR_SEARCH }} characters</p>
+    </mat-option>
+
+    <mat-option
+      class="result-hint"
+      *ngIf="
+        results.length === 0 &&
+        searchInput.value.length >= MIN_CHARACTERS_FOR_SEARCH &&
+        !isSearching
+      "
+    >
+      <p>There were no results</p>
+    </mat-option>
+
+    <mat-option class="result-hint" *ngIf="isSearching">
+      <p>Search in progress...</p>
+    </mat-option>
+
+    <mat-option *ngFor="let res of results" [value]="">
+      <app-child-block
+        *ngIf="res.getType() === 'Child'"
+        [entity]="res"
+        [ngClass]="{ 'result-inactive': !res.isActive() }"
+      ></app-child-block>
+      <app-school-block
+        *ngIf="res.getType() === 'School'"
+        [entity]="res"
+      ></app-school-block>
     </mat-option>
   </mat-autocomplete>
 </div>
 
-<button mat-icon-button fxHide.xs="false" fxHide="true" (click)="toggleSearchToolbar()">
+<button
+  mat-icon-button
+  fxHide.xs="false"
+  fxHide="true"
+  (click)="toggleSearchToolbar()"
+>
   <mat-icon class="header-icon" fontIcon="fa-search"></mat-icon>
 </button>
 
-<mat-toolbar *ngIf="showSearchToolbar" class="search-header mat-elevation-z7 mat-typography">
+<mat-toolbar
+  *ngIf="showSearchToolbar"
+  class="search-header mat-elevation-z7 mat-typography"
+>
   <mat-toolbar-row fxLayout="row">
-    <span matPrefix><mat-icon class="search-icon" fontIcon="fa-search"></mat-icon>&nbsp;</span>
-    <input #searchInput fxFlex="grow" matInput (input)="search()" title="Search" [matAutocomplete]="autoResults" [(ngModel)]="searchText">
-    {{searchInput.focus()}}
-    <button mat-icon-button (click)="toggleSearchToolbar()"><mat-icon class="search-icon" fontIcon="fa-times"></mat-icon></button>
+    <span matPrefix>
+      <mat-icon class="search-icon" fontIcon="fa-search"></mat-icon>
+    </span>
+    <input
+      #searchInput
+      fxFlex="grow"
+      matInput
+      title="Search"
+      [matAutocomplete]="autoResults"
+      [(ngModel)]="searchText"
+      (ngModelChange)="searchStringChanged.next($event)"
+    />
+    {{ searchInput.focus() }}
+    <button mat-icon-button (click)="toggleSearchToolbar()">
+      <mat-icon class="search-icon" fontIcon="fa-times"></mat-icon>
+    </button>
   </mat-toolbar-row>
 </mat-toolbar>

src/app/core/ui/search/search.component.scss

@@ -4,12 +4,20 @@
 
 .search-field {
   color: white;
+
+  span {
+    margin-right: 6px;
+  }
 }
 
 .result-inactive {
   color: grey;
 }
 
+.desktop-search-bar {
+  font-size: 16px;
+}
+
 .search-header {
   position: fixed;
   background: white;
@@ -23,3 +31,10 @@
   color: white;
   font-size: 15pt;
 }
+
+.result-hint {
+  background-color: lightgrey;
+  font-style: italic;
+  font-size: 14px;
+  height: 36px;
+}

src/app/core/ui/search/search.component.spec.ts

@@ -60,9 +60,28 @@ describe("SearchComponent", () => {
     expect(mockDatabase.saveDatabaseIndex).toHaveBeenCalled();
   });
 
+  it("should not search for less than MIN_CHARACTERS_FOR_SEARCH character of input", async () => {
+    let result = await component.startSearch("A");
+    component.handleSearchQueryResult(result);
+    expect(mockDatabase.query).not.toHaveBeenCalled();
+    expect(component.results).toEqual([]);
+
+    result = await component.startSearch("AB");
+    component.handleSearchQueryResult(result);
+    expect(mockDatabase.query).not.toHaveBeenCalled();
+    expect(component.results).toEqual([]);
+  });
+
   it("should not search for less than one real character of input", async () => {
-    component.searchText = "   ";
-    await component.search();
+    const result = await component.startSearch("   ");
+    component.handleSearchQueryResult(result);
+    expect(mockDatabase.query).not.toHaveBeenCalled();
+    expect(component.results).toEqual([]);
+  });
+
+  it("should reset results if a a null search is performed", async () => {
+    const result = await component.startSearch(null);
+    component.handleSearchQueryResult(result);
     expect(mockDatabase.query).not.toHaveBeenCalled();
     expect(component.results).toEqual([]);
   });
@@ -81,8 +100,8 @@ describe("SearchComponent", () => {
     };
     mockDatabase.query.and.returnValue(Promise.resolve(mockQueryResults));
 
-    component.searchText = "A";
-    await component.search();
+    const result = await component.startSearch("Ada");
+    component.handleSearchQueryResult(result);
     expect(mockDatabase.query).toHaveBeenCalled();
     expect(component.results).toEqual([child1, school1]);
   });
@@ -99,8 +118,8 @@ describe("SearchComponent", () => {
     };
     mockDatabase.query.and.returnValue(Promise.resolve(mockQueryResults));
 
-    component.searchText = "A";
-    await component.search();
+    const result = await component.startSearch("Ada");
+    component.handleSearchQueryResult(result);
     expect(mockDatabase.query).toHaveBeenCalled();
     expect(component.results.length).toBe(1);
     expect(component.results).toEqual([child1]);
@@ -120,8 +139,8 @@ describe("SearchComponent", () => {
     };
     mockDatabase.query.and.returnValue(Promise.resolve(mockQueryResults));
 
-    component.searchText = "A X";
-    await component.search();
+    const result = await component.startSearch("A X");
+    component.handleSearchQueryResult(result);
     expect(mockDatabase.query).toHaveBeenCalled();
     expect(component.results).toEqual([child1]);
   });

src/app/core/ui/search/search.component.ts

@@ -4,6 +4,11 @@ import { Child } from "../../../child-dev-project/children/model/child";
 import { School } from "../../../child-dev-project/schools/model/school";
 import { Entity } from "../../entity/entity";
 import { EntitySchemaService } from "../../entity/schema/entity-schema.service";
+import { Subject } from "rxjs";
+import { debounceTime, switchMap } from "rxjs/operators";
+import { LoggingService } from "../../logging/logging.service";
+import { LogLevel } from "../../logging/log-level";
+import { AlertService } from "../../alerts/alert.service";
 
 /**
  * General search box that provides results out of any kind of entities from the system
@@ -20,17 +25,113 @@ export class SearchComponent implements OnInit {
   results = [];
   searchText = "";
   showSearchToolbar = false;
+  isSearching: boolean = false;
+
+  MIN_CHARACTERS_FOR_SEARCH: number = 3;
+  INPUT_DEBOUNCE_TIME_MS: number = 400;
+
+  searchStringChanged: Subject<string> = new Subject<string>();
+  searchQuery: Subject<Promise<any>> = new Subject<Promise<any>>();
 
   constructor(
     private db: Database,
-    private entitySchemaService: EntitySchemaService
+    private entitySchemaService: EntitySchemaService,
+    private loggingService: LoggingService,
+    private alertService: AlertService
   ) {}
 
   ngOnInit() {
     this.createSearchIndex();
+
+    this.searchStringChanged
+      .pipe(debounceTime(this.INPUT_DEBOUNCE_TIME_MS))
+      .subscribe((searchString) => {
+        this.searchQuery.next(this.startSearch(searchString));
+      });
+
+    this.searchQuery
+      .pipe(
+        switchMap((value) => {
+          return value;
+        })
+      )
+      .subscribe(
+        (result: { queryResults: any; searchTerms: string[] }) => {
+          this.handleSearchQueryResult(result);
+        },
+        (error) => {
+          this.loggingService.log(
+            {
+              message: "[Search] An error has occurred in a search query.",
+              error,
+            },
+            LogLevel.ERROR
+          );
+          this.alertService.addWarning(
+            "An error has occurred in your search query. Please try again."
+          );
+        }
+      );
+  }
+
+  async startSearch(searchString: string): Promise<any> {
+    this.isSearching = true;
+    this.results = [];
+
+    if (!searchString) {
+      return Promise.resolve();
+    }
+
+    searchString = searchString.toLowerCase();
+
+    if (!this.isRelevantSearchInput(searchString)) {
+      return Promise.resolve();
+    }
+
+    const searchTerms = searchString.split(" ");
+
+    const queryResults = await this.db.query("search_index/by_name", {
+      startkey: searchTerms[0],
+      endkey: searchTerms[0] + "\ufff0",
+      include_docs: true,
+    });
+
+    return {
+      queryResults,
+      searchTerms,
+    };
+  }
+
+  clickOption(optionElement) {
+    // simulate a click on the EntityBlock inside the selected option element
+    optionElement._element.nativeElement.children["0"].children["0"].click();
+    if (this.showSearchToolbar === true) {
+      this.showSearchToolbar = false;
+    }
+  }
+
+  toggleSearchToolbar() {
+    this.showSearchToolbar = !this.showSearchToolbar;
   }
 
-  private createSearchIndex() {
+  handleSearchQueryResult(result: {
+    queryResults: any;
+    searchTerms: string[];
+  }) {
+    this.isSearching = false;
+
+    if (!result || !result.queryResults) {
+      this.results = [];
+      return;
+    }
+
+    this.results = this.prepareResults(
+      result.queryResults.rows,
+      result.searchTerms
+    );
+  }
+
+  private createSearchIndex(): Promise<any> {
     // `emit(x)` to add x as a key to the index that can be searched
     const searchMapFunction =
       "(doc) => {" +
@@ -46,28 +147,7 @@ export class SearchComponent implements OnInit {
       },
     };
 
-    this.db.saveDatabaseIndex(designDoc);
-  }
-
-  async search() {
-    this.searchText = this.searchText.toLowerCase();
-    if (!this.isRelevantSearchInput(this.searchText)) {
-      this.results = [];
-      return;
-    }
-
-    const searchHash = JSON.stringify(this.searchText);
-    const searchTerms = this.searchText.split(" ");
-    const queryResults = await this.db.query("search_index/by_name", {
-      startkey: searchTerms[0],
-      endkey: searchTerms[0] + "\ufff0",
-      include_docs: true,
-    });
-
-    if (JSON.stringify(this.searchText) === searchHash) {
-      // only set result if the user hasn't continued typing and changed the search term already
-      this.results = this.prepareResults(queryResults.rows, searchTerms);
-    }
+    return this.db.saveDatabaseIndex(designDoc);
   }
 
   /**
@@ -77,10 +157,13 @@ export class SearchComponent implements OnInit {
    */
   private isRelevantSearchInput(searchText: string) {
     const regexp = new RegExp("[a-z]+|[0-9]+");
-    return this.searchText.match(regexp);
+    return (
+      searchText.match(regexp) &&
+      searchText.length >= this.MIN_CHARACTERS_FOR_SEARCH
+    );
   }
 
-  private prepareResults(rows, searchTerms: string[]) {
+  private prepareResults(rows, searchTerms: string[]): any[] {
     return this.getResultsWithoutDuplicates(rows)
       .map((doc) => this.transformDocToEntity(doc))
       .filter((r) => r !== null)
@@ -150,16 +233,4 @@ export class SearchComponent implements OnInit {
 
     return t[0].localeCompare(t[1]);
   }
-
-  clickOption(optionElement) {
-    // simulate a click on the EntityBlock inside the selected option element
-    optionElement._element.nativeElement.children["0"].children["0"].click();
-    if (this.showSearchToolbar === true) {
-      this.showSearchToolbar = false;
-    }
-  }
-
-  toggleSearchToolbar() {
-    this.showSearchToolbar = !this.showSearchToolbar;
-  }
 }