Feat/scrollspy

src/app/app.component.html

@@ -4,7 +4,7 @@
     <mat-sidenav mode="side">
       <rxjs-docs-sidenav></rxjs-docs-sidenav>
     </mat-sidenav>
-    <mat-sidenav-content>
+    <mat-sidenav-content cdkScrollable>
       <router-outlet></router-outlet>
     </mat-sidenav-content>
   </mat-sidenav-container>

src/app/app.module.ts

@@ -9,6 +9,7 @@ import { MarkdownModule } from 'ngx-markdown';
 import { SharedModule } from './shared/shared.module';
 import { HttpClientModule, HttpClient } from '@angular/common/http';
 import { FontAwesomeModule } from '@fortawesome/angular-fontawesome';
+import { ScrollingModule } from '@angular/cdk/scrolling';
 
 @NgModule({
   declarations: [AppComponent],
@@ -21,6 +22,7 @@ import { FontAwesomeModule } from '@fortawesome/angular-fontawesome';
     SharedModule,
     MarkdownModule.forRoot({ loader: HttpClient }),
     FontAwesomeModule,
+    ScrollingModule,
   ],
   providers: [],
   bootstrap: [AppComponent],

src/app/shared/components/scroll-spy/scroll-spy.component.css

@@ -0,0 +1,40 @@
+.root {
+  padding: 4px;
+  padding-left: 8px;
+  display: inline-table;
+  position: sticky;
+  top: 20px;
+  border-left: 1px solid gray;
+  display: inline-table;
+}
+
+.section {
+  display: flex;
+  align-items: center;
+  margin-bottom: 0.6em;
+  cursor: pointer;
+  transition: all 0.3s;
+}
+
+.actual-section-indicator {
+  width: 0;
+  height: 10px;
+  margin-left: -17px;
+  margin-right: 15px;
+  border-radius: 100px;
+  background-color: white;
+  border: 1px solid white;
+  flex: none;
+  display: inline-block;
+  transition: all 0.3s;
+}
+
+.section:hover {
+  color: rgb(148, 7, 78);
+}
+
+.actual-section-indicator.active {
+  width: 16px;
+  margin-right: 5px;
+  border: 1px solid black;
+}

src/app/shared/components/scroll-spy/scroll-spy.component.html

@@ -0,0 +1,13 @@
+<div class="root">
+  <a
+    class="section"
+    *ngFor="let section of sections"
+    (click)="scrollTo(section.id)"
+  >
+    <span
+      class="actual-section-indicator"
+      [class.active]="isActualSection(section.id)"
+    ></span>
+    <span>{{ section.name }}</span>
+  </a>
+</div>

src/app/shared/components/scroll-spy/scroll-spy.component.spec.ts

@@ -0,0 +1,25 @@
+import { async, ComponentFixture, TestBed } from '@angular/core/testing';
+
+import { ScrollSpyComponent } from './scroll-spy.component';
+
+describe('ScrollSpyComponent', () => {
+  let component: ScrollSpyComponent;
+  let fixture: ComponentFixture<ScrollSpyComponent>;
+
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      declarations: [ ScrollSpyComponent ]
+    })
+    .compileComponents();
+  }));
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(ScrollSpyComponent);
+    component = fixture.componentInstance;
+    fixture.detectChanges();
+  });
+
+  it('should create', () => {
+    expect(component).toBeTruthy();
+  });
+});

src/app/shared/components/scroll-spy/scroll-spy.component.ts

@@ -0,0 +1,88 @@
+import {
+  Component,
+  AfterContentChecked,
+  ChangeDetectorRef,
+  OnInit,
+} from '@angular/core';
+import { debounce, throttle, debounceTime } from 'rxjs/operators';
+import { ScrollDispatcher, CdkScrollable } from '@angular/cdk/overlay';
+import { interval } from 'rxjs';
+
+@Component({
+  selector: 'rxjs-scroll-spy',
+  templateUrl: './scroll-spy.component.html',
+  styleUrls: ['./scroll-spy.component.css'],
+})
+export class ScrollSpyComponent implements AfterContentChecked, OnInit {
+  currentSection = '';
+  sections = [];
+  private sectionsHeader: NodeListOf<HTMLHeadingElement>;
+
+  constructor(
+    private scroll: ScrollDispatcher,
+    private changeDetector: ChangeDetectorRef
+  ) {}
+
+  ngOnInit() {
+    this.scroll
+      .scrolled()
+      .pipe(throttle((ev) => interval(100)))
+      .subscribe((scroll: CdkScrollable) => this.onScroll(scroll));
+  }
+
+  ngAfterContentChecked(): void {
+    this.loadSections();
+  }
+
+  scrollTo(sectionId) {
+    document.querySelector('#' + sectionId).scrollIntoView();
+  }
+
+  isActualSection(sectionId: string) {
+    return sectionId === this.currentSection;
+  }
+
+  private loadSections() {
+    this.sectionsHeader = document.querySelectorAll('h2');
+    this.sections = [];
+    this.sectionsHeader.forEach((header: HTMLHeadingElement) => {
+      this.sections.push({
+        name: header.textContent,
+        id: header.id,
+      });
+    });
+  }
+
+  private onScroll(scroll: CdkScrollable) {
+    const scrollTop = scroll.getElementRef().nativeElement.scrollTop || 0;
+    const parentOffset = scroll.getElementRef().nativeElement.offsetTop;
+    const currentSection = this.getCurrentSection({ scrollTop, parentOffset });
+
+    if (!currentSection || currentSection.id === this.currentSection) {
+      return;
+    }
+
+    this.currentSection = currentSection.id;
+    this.changeDetector.detectChanges();
+  }
+
+  private getCurrentSection({ scrollTop, parentOffset }) {
+    const sectionsCount = this.sectionsHeader.length;
+    let actualHeader;
+    for (let i = 0; i < sectionsCount; i++) {
+      const header = this.sectionsHeader[i];
+      if (header.offsetTop - parentOffset <= scrollTop) {
+        actualHeader = header;
+      }
+    }
+
+    return actualHeader;
+
+    /* For some reason, this (and similar) DONT work. Only get first element
+     return [].find.call(
+      this.sectionsHeader,
+      (header: HTMLHeadingElement) =>
+        header.offsetTop - parentOffset <= scrollTop
+    ); */
+  }
+}

src/app/shared/shared.module.ts

@@ -23,10 +23,16 @@ import { NgModule } from '@angular/core';
 import { MatDividerModule } from '@angular/material/divider';
 import { SidenavComponent } from './components/sidenav/sidenav.component';
 import { RouterModule } from '@angular/router';
+import { ScrollSpyComponent } from './components/scroll-spy/scroll-spy.component';
 
 const CORE_MODULES = [CommonModule, FormsModule, ReactiveFormsModule];
 
-const COMPONENTS = [FooterComponent, HeaderComponent, SidenavComponent];
+const COMPONENTS = [
+  FooterComponent,
+  HeaderComponent,
+  SidenavComponent,
+  ScrollSpyComponent,
+];
 
 const MATERIAL_MODULES = [
   MatInputModule,
@@ -49,7 +55,7 @@ const MATERIAL_MODULES = [
 ];
 
 @NgModule({
-  declarations: COMPONENTS,
+  declarations: [COMPONENTS, ScrollSpyComponent],
   imports: [MATERIAL_MODULES, CORE_MODULES, FlexLayoutModule],
   exports: [COMPONENTS, MATERIAL_MODULES, CORE_MODULES, FlexLayoutModule],
 })

src/app/views/home/content/content.component.css

@@ -1,3 +1,12 @@
+.md-container {
+  display: flex;
+}
+
+.md-container > * {
+  margin: 0 24px;
+  min-width: 0; /* Fix flex horizontal overflow */
+}
+
 details {
   border-top: 2px solid #e3e7e7;
   margin: 50px 0 0;
@@ -65,6 +74,10 @@ th {
   padding: 25px;
 }
 
+.scrollspy-container {
+  max-width: 450px;
+}
+
 .page-heading {
   display: flex;
   justify-content: space-between;
@@ -114,3 +127,10 @@ summary:hover {
     padding: 40px;
   }
 }
+
+@media only screen and (max-width: 700px) {
+  .scrollspy-container {
+    display: none;
+  }
+}
+

src/app/views/home/content/content.component.html

@@ -1,3 +1,8 @@
 <div class="md-container">
-  <scully-content></scully-content>
+  <div class="scully-content-container">
+    <scully-content></scully-content>
+  </div>
+  <div class="scrollspy-container">
+    <rxjs-scroll-spy></rxjs-scroll-spy>
+  </div>
 </div>