Class MockResizeObserver

lib/utils/test/mockResizeObserver.ts:73–159

}

class MockResizeObserver implements ResizeObserver {
  readonly #callback: ResizeObserverCallback;
  #disconnected: boolean = false;
  #elements: Set<HTMLElement> = new Set();

  constructor(callback: ResizeObserverCallback) {
    this.#callback = callback;

    emitter.addListener("change", this.#onChange);
  }

  observe(element: HTMLElement) {
    if (this.#disconnected) {
      return;
    }

    this.#elements.add(element);
    this.#notify([element]);
  }

  unobserve(element: HTMLElement) {
    this.#elements.delete(element);
  }

  disconnect() {
    this.#disconnected = true;
    this.#elements.clear();

    emitter.removeListener("change", this.#onChange);
  }

  #notify(elements: HTMLElement[]) {
    if (disabled) {
      return;
    }

    const entries = elements.map((element) => {
      const computedStyle = window.getComputedStyle(element);
      const writingMode = computedStyle.writingMode;

      let contentRect: DOMRectReadOnly =
        elementToDOMRect.get(element) ?? defaultDomRect;

      if (getDOMRect) {
        const contentRectOverride = getDOMRect(element);
        if (contentRectOverride) {
          contentRect = contentRectOverride;
        }
      }

      let blockSize = 0;
      let inlineSize = 0;
      if (writingMode.includes("vertical")) {
        blockSize = contentRect.width;
        inlineSize = contentRect.height;
      } else {
        blockSize = contentRect.height;
        inlineSize = contentRect.width;