# All files / src/test-utils ResizeObserver.ts

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     import { afterEach, jest } from "@jest/globals";
    import {
      resizeObserverManager,
      type ResizeObserverManager,
    } from "../useResizeObserver.js";

    /**
     * @remarks \@since 6.0.0
     */
    export interface ResizeObserverEntrySize {
      height?: number;
      width?: number;
    }

    /**
     * @remarks \@since 6.0.0
     */
    export type GetResizeObserverEntryMock = (
      target: Element,
      size?: ResizeObserverEntrySize
    ) => ResizeObserverEntry;

    /**
     * This is mostly an internal function to be used with the {@link ResizeObserverMock}
     * and {@link setupResizeObserverMock}
     *
     * @remarks \@since 6.0.0
     */
    export const createResizeObserverEntry: GetResizeObserverEntryMock = (
      target,
      size
    ) => {
      const contentRect = target.getBoundingClientRect();
      if (typeof size?.height === "number") {
        contentRect.height = size.height;
      }
      if (typeof size?.width === "number") {
        contentRect.width = size.width;
      }

      const boxSize: ResizeObserverSize = {
        blockSize: contentRect.height,
        inlineSize: contentRect.width,
      };

      return {
        target,
        contentRect,
        borderBoxSize: [boxSize],
        contentBoxSize: [boxSize],
        devicePixelContentBoxSize: [],
      };
    };

    /**
     * This is the default ResizeObserver implementation if it does not already
     * exist in jsdom. You normally should not use this directly and instead use the
     * {@link setupResizeObserverMock} instead.
     *
     * @remarks \@since 6.0.0
     */
    export class ResizeObserverMock implements ResizeObserver {
      elements: Set<Element>;

      constructor(public callback: ResizeObserverCallback) {
        this.elements = new Set();
      }

      observe = (target: Element): void => {
        this.elements.add(target);
        this.resizeAllElements(createResizeObserverEntry);
      };

      unobserve = (target: Element): void => {
        this.elements.delete(target);
      };

      disconnect = (): void => {
        this.elements.clear();
      };

      /**
       * Triggers the resize event for a specific element. This must be wrapped in
       * `act`.
       *
       * @example
       * Main Usage
       * ```tsx
       * import {
       *   cleanupResizeObserverAfterEach,
       *   setupResizeObserverMock,
       * } from "@react-md/core/test-utils";
       * import { useResizeObserver } from "@react-md/core";
       * import { ExampleComponent } from "../ExampleComponent.js";
       *
       * cleanupResizeObserverAfterEach();
       *
       * describe("ExampleComponent", () => {
       *   it("should do stuff", () => {
       *     const observer = setupResizeObserverMock();
       *     render(<ExampleComponent />)
       *
       *     const resizeTarget = screen.getByTestId("resize-target")
       *
       *     // you can trigger with a custom change
       *     act(() => {
       *       observer.resizeElement(resizeTarget, { height: 100, width: 100 });
       *     });
       *     // expect resize changes
       *   });
       * })
       * ```
       */
      resizeElement = (
        target: Element,
        changesOrGetEntry:
          | GetResizeObserverEntryMock
          | ResizeObserverEntrySize
          | ResizeObserverEntry = createResizeObserverEntry
      ): void => {
        if (!this.elements.has(target)) {
          throw new Error(
            "The `ResizeObserverMock` is not watching the target element and cannot be resized"
          );
        }

        let entry: ResizeObserverEntry;
        if (typeof changesOrGetEntry === "function") {
          entry = changesOrGetEntry(target);
        } else if (!("contentRect" in changesOrGetEntry)) {
          entry = createResizeObserverEntry(target, changesOrGetEntry);
        } else {
          entry = changesOrGetEntry;
        }

        this.callback([entry], this);
      };

      /**
       * You'll normally want to use {@link resizeElement} instead, but this can be
       * used to resize all the watched elements at once.
       *
       * @example
       * ```tsx
       * import {
       *   act,
       *   createResizeObserverEntry,
       *   render,
       *   screen,
       *   setupResizeObserverMock,
       * } from "@react-md/core/test-utils";
       *
       * const observer = setupResizeObserverMock();
       * const { container } = render(<Test />)
       * expect(container).toMatchSnapshot()
       *
       * const target1 = screen.getByTestId('target-1');
       * const target2 = screen.getByTestId('target-2');
       * const target3 = screen.getByTestId('target-3');
       *
       * act(() => {
       *   observer.resizeAllElements((element) => {
       *     let height: number | undefined;
       *     let width: number | undefined;
       *     switch (element) {
       *       case target1:
       *         height = 400;
       *         width = 250;
       *         break;
       *       case target2:
       *         height = 100;
       *         width = 380;
       *         break;
       *       case target3:
       *         height = 24;
       *         width = 24;
       *         break;
       *     }
       *
       *     return createResizeObserverEntry(element, { height, width });
       *   });
       * });
       * expect(container).toMatchSnapshot()
       * ```
       */
      resizeAllElements = (getEntry = createResizeObserverEntry): void => {
        const entries = [...this.elements].map((element) => getEntry(element));
        this.callback(entries, this);
      };
    }

    /**
     * @remarks \@since 6.0.0
     */
    export interface SetupResizeObserverMockOptions {
      /**
       * Set this to `true` to mimic the real `ResizeObserver` behavior where the
       * updates occur after an animation frame instead of invoking immediately.
       *
       * Keeping this as `false` is recommended since this option was only added to
       * make testing this function itself easier.
       *
       * @defaultValue `false`
       */
      raf?: boolean;

      /**
       * Keeping this as the `resizeObserverManager` is recommended since this
       * option was only added to make testing this function easier itself.
       *
       * @defaultValue `resizeObserverManager`
       */
      manager?: ResizeObserverManager;
    }

    /**
     * Initializes the `ResizeObserverMock` to be used for tests.
     *
     * @example
     * Main Usage
     * ```tsx
     * import { useCallback, useState } from "react";
     * import {
     *   cleanupResizeObserverAfterEach,
     *   render,
     *   screen,
     *   setupResizeObserverMock,
     * } from "@react-md/core/test-utils";
     * import { useResizeObserver } from "@react-md/core";
     *
     * function ExampleComponent() {
     *   const [size, setSize] = useState({ height: 0, width: 0 });
     *   const ref = useResizeObserver({
     *     onUpdate: useCallback((entry) => {
     *       setSize({
     *         height: entry.contentRect.height,
     *         width: entry.contentRect.width,
     *       });
     *     });
     *   });
     *
     *   return (
     *     <>
     *       <div data-testid="size">{JSON.stringify(size)}</div>
     *       <div data-testid="resize-target" ref={ref} />
     *     </>
     *   );
     * }
     *
     * cleanupResizeObserverAfterEach();
     *
     * describe("ExampleComponent", () => {
     *   it("should do stuff", () => {
     *     const observer = setupResizeObserverMock();
     *     render(<ExampleComponent />)
     *
     *     const size = screen.getByTestId("size");
     *     const resizeTarget = screen.getByTestId("resize-target")
     *
     *     // jsdom sets all element sizes to 0 by default
     *     expect(size).toHaveTextContent(JSON.stringify({ height: 0, width: 0 }));
     *
     *     // you can trigger with a custom change
     *     act(() => {
     *       observer.resizeElement(resizeTarget, { height: 100, width: 100 });
     *     });
     *     expect(size).toHaveTextContent(JSON.stringify({ height: 100, width: 100 }));
     *
     *     // or you can mock the `getBoundingClientRect` result
     *     jest.spyOn(resizeTarget, "getBoundingClientRect")
     *       .mockReturnValue({
     *         ...document.body.getBoundingClientRect(),
     *         height: 200,
     *         width: 200,
     *       }):
     *
     *     act(() => {
     *       observer.resizeElement(resizeTarget);
     *     });
     *     expect(size).toHaveTextContent(JSON.stringify({ height: 200, width: 200 }));
     *   });
     * })
     * ```
     *
     * @remarks \@since 6.0.0
     */
    export function setupResizeObserverMock(
      options: SetupResizeObserverMockOptions = {}
    ): ResizeObserverMock {
      const { raf, manager = resizeObserverManager } = options;

      const resizeObserver = new ResizeObserverMock((entries) => {
        if (raf) {
          window.cancelAnimationFrame(manager.frame);
          manager.frame = window.requestAnimationFrame(() => {
            manager.handleResizeEntries(entries);
          });
        } else {
          manager.handleResizeEntries(entries);
        }
      });
      manager.sharedObserver = resizeObserver;
      return resizeObserver;
    }

    /**
     * @see {@link setupResizeObserverMock}
     * @remarks \@since 6.0.0
     */
    export function cleanupResizeObserverAfterEach(restoreAllMocks = true): void {
      afterEach(() => {
        resizeObserverManager.frame = 0;
        resizeObserverManager.subscriptions = new Map();
        resizeObserverManager.sharedObserver = undefined;

        if (restoreAllMocks) {
          jest.restoreAllMocks();
        }
      });
    }