#274 reset page properly when out of bounds

src/app/pdf-viewer/pdf-viewer.component.spec.ts

@@ -1,4 +1,4 @@
-import { TestBed, async } from '@angular/core/testing';
+import { TestBed, async, ComponentFixture } from '@angular/core/testing';
 import { Component } from '@angular/core';
 
 import { PdfViewerComponent } from './pdf-viewer.component';
@@ -10,6 +10,9 @@ import { PdfViewerModule } from './pdf-viewer.module';
 class TestComponent {}
 
 describe('AppComponent', () => {
+  let pdfViewerFixture: ComponentFixture<PdfViewerComponent>;
+  let pdfViewer: PdfViewerComponent;
+
   beforeEach(async(() => {
     TestBed.configureTestingModule({
       declarations: [
@@ -23,7 +26,39 @@ describe('AppComponent', () => {
 
   it('should create test component', async(() => {
     const fixture = TestBed.createComponent(TestComponent);
+    pdfViewerFixture = TestBed.createComponent(PdfViewerComponent);
     const app = fixture.debugElement.componentInstance;
+    pdfViewer = pdfViewerFixture.debugElement.componentInstance;
     expect(app).toBeTruthy();
+    expect(pdfViewer).toBeTruthy();
   }));
+
+  describe('getValidPageNumber', () => {
+    function setPdf(numPages: number) {
+      (pdfViewer as any)._pdf = {
+        numPages
+      };
+    }
+
+    it('should return page if between first and last pages', () => {
+      setPdf(10);
+
+      [1, 3, 7, 10].forEach((page: number) => {
+        expect((pdfViewer as any).getValidPageNumber(page)).toBe(page, `page: ${ page }`);
+      });
+    });
+
+    it('should return last page', function () {
+      const pages = 100;
+      setPdf(pages);
+      expect((pdfViewer as any).getValidPageNumber(pages + 1)).toBe(pages);
+      expect((pdfViewer as any).getValidPageNumber(pages + 2)).toBe(pages);
+    });
+
+    it('should return first page when page is less then 1', function () {
+      setPdf(10);
+      expect((pdfViewer as any).getValidPageNumber(0)).toBe(1);
+      expect((pdfViewer as any).getValidPageNumber(-1)).toBe(1);
+    });
+  });
 });

src/app/pdf-viewer/pdf-viewer.component.ts

@@ -47,6 +47,7 @@ export class PdfViewerComponent implements OnChanges, OnInit {
   @Output('after-load-complete') afterLoadComplete = new EventEmitter<PDFDocumentProxy>();
   @Output('error') onError = new EventEmitter<any>();
   @Output('on-progress') onProgress = new EventEmitter<PDFProgressData>();
+  @Output() pageChange: EventEmitter<number> = new EventEmitter<number>(true);
 
   constructor(private element: ElementRef) {
     if (!isSSR() && typeof PDFJS.workerSrc !== 'string') {
@@ -95,18 +96,16 @@ export class PdfViewerComponent implements OnChanges, OnInit {
 
   @Input('page')
   set page(_page) {
-    _page = parseInt(_page, 10);
+    _page = parseInt(_page, 10) || 1;
 
-    if (this._pdf && !this.isValidPageNumber(_page)) {
-      _page = 1;
+    if (this._pdf) {
+      _page = this.getValidPageNumber(_page);
     }
 
     this._page = _page;
     this.pageChange.emit(_page);
   }
 
-  @Output() pageChange: EventEmitter<number> = new EventEmitter<number>(true);
-
   @Input('render-text')
   set renderText(renderText: boolean) {
     this._renderText = renderText;
@@ -203,8 +202,16 @@ export class PdfViewerComponent implements OnChanges, OnInit {
     });
   }
 
-  private isValidPageNumber(page: number): boolean {
-    return this._pdf.numPages >= page && page >= 1;
+  private getValidPageNumber(page: number): number {
+    if (page < 1) {
+      return 1;
+    }
+
+    if (page > this._pdf.numPages) {
+      return this._pdf.numPages;
+    }
+
+    return page;
   }
 
   static getLinkTarget(type: string) {
@@ -289,9 +296,7 @@ export class PdfViewerComponent implements OnChanges, OnInit {
   }
 
   private renderMultiplePages() {
-    if (!this.isValidPageNumber(this._page)) {
-      this._page = 1;
-    }
+    this._page = this.getValidPageNumber(this._page);
 
     if (this._rotation !== 0 || this.pdfViewer.pagesRotation !== this._rotation) {
       setTimeout(() => {