Skip to content

fix: make content anchors more accurate #165

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
zaucy wants to merge 1 commit into
base: main
Choose a base branch
from
Draft

fix: make content anchors more accurate #165

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion src/components/layout/content/content.component.html
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,7 @@
[replaceUrl]="true"
[fragment]="pageAnchor.id"
[style.padding-left]="pageAnchor.indent * 8"
[class.active]="activePageAnchorId === pageAnchor.id">
[class.active]="activePageAnchorIds.indexOf(pageAnchor.id) !== -1">
{{ pageAnchor.title }}
</a>
</div>
Expand Down
73 changes: 23 additions & 50 deletions src/components/layout/content/content.component.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,10 +68,9 @@ function getAnchorTitleText(element: Element): string {
imports: [CdkObserveContent, NgIf, RouterLink, NgFor, AsyncPipe],
})
export class ContentComponent implements OnInit, OnDestroy {
private _anchorEventListenerCleanupFns: (() => void)[] = [];
private _intersectionObserver: IntersectionObserver;
private anchorCheckInterval: any;
pageAnchors: ContentPageAnchor[] = [];
activePageAnchorId: string = '';
activePageAnchorIds: string[] = [];
wantsScrollTo: string = '';

@ViewChild('mainContent', {static: true})
Expand Down Expand Up @@ -113,41 +112,36 @@ export class ContentComponent implements OnInit, OnDestroy {
}
}

private onIntersect(entries: IntersectionObserverEntry[]) {
const entry = entries[0];
if (entry.boundingClientRect.top < 90) {
if (entry.isIntersecting) {
for (let i = 0; this.pageAnchors.length > i; ++i) {
if (this.pageAnchors[i].id == entry.target.id) {
const prevIndex = i - 1;
if (prevIndex > 0) {
this.activePageAnchorId = this.pageAnchors[prevIndex].id;
} else {
this.activePageAnchorId = entry.target.id;
}

this.cdr.detectChanges();
break;
}
}
} else {
this.activePageAnchorId = entry.target.id;
this.cdr.detectChanges();
checkActivePageAnchors() {
let newActiveAnchorIds: [string, number][] = [];
for (const anchor of this.pageAnchors) {
const rect = anchor.element.getBoundingClientRect();
if (rect.top > -50 && rect.top < 90) {
newActiveAnchorIds.push([anchor.id, rect.top]);
}
}

if (newActiveAnchorIds.length > 0) {
if (newActiveAnchorIds.length > 1) {
newActiveAnchorIds = newActiveAnchorIds.filter(
([_, top]) => Math.abs(top) < 50,
);
}

this.activePageAnchorIds = newActiveAnchorIds.map(([id]) => id);
this.cdr.detectChanges();
}
}

ngOnInit(): void {
this._intersectionObserver = new IntersectionObserver(
entries => this.onIntersect(entries),
{rootMargin: '-90px 0px 0px 0px'},
);

this.anchorCheckInterval = setInterval(() => {
this.checkActivePageAnchors();
}, 500);
this.refreshPageAnchors();
}

ngOnDestroy(): void {
this._intersectionObserver.disconnect();
clearInterval(this.anchorCheckInterval);
}

onContentChange(changes: MutationRecord[]) {
Expand Down Expand Up @@ -187,14 +181,6 @@ export class ContentComponent implements OnInit, OnDestroy {
}

private createPageAnchor(element: Element) {
const eventHandler = ev => {
this.activePageAnchorId = element.id;
this.cdr.detectChanges();
};
element.addEventListener('mouseover', eventHandler);
this._anchorEventListenerCleanupFns.push(() => {
element.removeEventListener('mouseover', eventHandler);
});
return {
id: element.id,
title: getAnchorTitleText(element),
Expand All @@ -204,15 +190,6 @@ export class ContentComponent implements OnInit, OnDestroy {
}

refreshPageAnchors() {
for (const fn of this._anchorEventListenerCleanupFns) {
fn();
}
this._anchorEventListenerCleanupFns = [];

for (const {element} of this.pageAnchors) {
this._intersectionObserver.unobserve(element);
}

const mainEl = this.mainContent!.nativeElement;
this.pageAnchors = Array.from(mainEl.querySelectorAll('[id]')).map(el =>
this.createPageAnchor(el),
Expand All @@ -229,10 +206,6 @@ export class ContentComponent implements OnInit, OnDestroy {
this.pageAnchors.forEach(item => (item.indent -= smallestIndent));
}

for (const {element} of this.pageAnchors) {
this._intersectionObserver.observe(element);
}

this.cdr.detectChanges();
this.consumeScrollToIfNeeded();
}
Expand Down