nostrweb/src/view.ts

import {DOMMap, renderViewTemplate, ViewTemplateOptions} from './template';

type Container = {
  id: string;
  options: ViewTemplateOptions,
  view: HTMLElement;
  content: HTMLDivElement;
  dom: DOMMap;
};

const containers: Array<Container> = [];

let activeContainerIndex = -1;

export const getViewContent = () => containers[activeContainerIndex]?.content;

/**
 * clears current view so it is empty and ready to be re-used.
 * only clears the current view, not all views
 */
export const clearView = () => {
  const domMap = containers[activeContainerIndex]?.dom;
  Object.keys(domMap).forEach(eventId => delete domMap[eventId]);
  getViewContent().replaceChildren();
};

/**
 * get elmenet stored in internal DOMMap of the current view
 * alternative to internal map in view.dom, is to use id="" attribute, however same event could be shown in different views so event.id is not unique.
 */
export const getViewElem = (id: string) => {
  return containers[activeContainerIndex]?.dom[id];
};

/**
 * store element in internal view.dom map using id as key
 */
export const setViewElem = (id: string, node: HTMLElement) => {
  const container = containers[activeContainerIndex];
  if (container) {
    container.dom[id] = node;
  }
  return node;
};

const mainContainer = document.querySelector('main') as HTMLElement;

const createContainer = (
  route: string,
  options: ViewTemplateOptions,
) => {
  const {content, dom, view} = renderViewTemplate(options);
  const container = {id: route, options, view, content, dom};
  mainContainer.append(view);
  containers.push(container);
  return container;
};

type GetViewOptions = () => ViewTemplateOptions;

/**
 * get options for current view
 * @returns {id: 'feed' | 'profile' | 'note' | 'event', id?: string}
 */
export const getViewOptions: GetViewOptions = () => containers[activeContainerIndex]?.options || {type: 'feed'};

/**
 * changes the current view and transitions to the view specified by route
 * example:
 *    view('/npub0293ji3gojaed32r4r412', {type: 'feed})
 */
export const view = (
  route: string,
  options: ViewTemplateOptions,
) => {
  const active = containers[activeContainerIndex];
  const nextContainer = containers.find(c => c.id === route) || createContainer(route, options);
  const nextContainerIndex = containers.indexOf(nextContainer);
  if (nextContainerIndex === activeContainerIndex) {
    return;
  }
  if (active) {
    nextContainer.view.classList.add('view-next');
  }
  requestAnimationFrame(() => {
    requestAnimationFrame(() => {
      nextContainer.view.classList.remove('view-next', 'view-prev');
    });
    active?.view.classList.add(nextContainerIndex < activeContainerIndex ? 'view-next' : 'view-prev');
    activeContainerIndex = nextContainerIndex;
  });
};