Class

packages/app-core/src/lib/cm-heading-fold.ts:280–312

const headingArrowPlugin = ViewPlugin.fromClass(
  class {
    private readonly view: EditorView
    decorations: DecorationSet

    private cursorFixFrame = 0

    constructor(view: EditorView) {
      this.view = view
      this.decorations = buildDecorations(view)
      this.cursorFixFrame = requestAnimationFrame(() => fixFatCursorHeight(this.view))
    }

    update(update: ViewUpdate): void {
      if (
        update.docChanged ||
        update.viewportChanged ||
        update.selectionSet ||
        update.transactions.some((tr) =>
          tr.effects.some((e) => e.is(foldEffect) || e.is(unfoldEffect))
        )
      ) {
        this.decorations = buildDecorations(update.view)
      }
      if (update.selectionSet || update.geometryChanged || update.docChanged || update.viewportChanged) {
        cancelAnimationFrame(this.cursorFixFrame)
        this.cursorFixFrame = requestAnimationFrame(() => fixFatCursorHeight(this.view))
      }
    }

    destroy(): void {
      cancelAnimationFrame(this.cursorFixFrame)
    }
  },
  {
    decorations: (plugin) => plugin.decorations
  }