@netdata/charts/dist/helpers/makeResizeObserver/index.test.js

Netdata frontend SDK and chart utilities

"use strict";

var _ = _interopRequireDefault(require("."));
function _interopRequireDefault(e) { return e && e.__esModule ? e : { "default": e }; }
describe("makeResizeObserver", function () {
  var mockElement;
  var mockObserver;
  var observeCallback;
  beforeEach(function () {
    jest.useFakeTimers();
    mockElement = {};
    mockObserver = {
      observe: jest.fn(),
      disconnect: jest.fn()
    };
    global.ResizeObserver = jest.fn(function (callback) {
      observeCallback = callback;
      return mockObserver;
    });
  });
  afterEach(function () {
    jest.useRealTimers();
    jest.restoreAllMocks();
  });
  it("creates and observes element", function () {
    var action = jest.fn();
    var initialAction = jest.fn();
    (0, _["default"])(mockElement, action, initialAction);
    expect(global.ResizeObserver).toHaveBeenCalledWith(expect.any(Function));
    expect(mockObserver.observe).toHaveBeenCalledWith(mockElement);
  });
  it("calls initialAction on first resize after delay", function () {
    var action = jest.fn();
    var initialAction = jest.fn();
    (0, _["default"])(mockElement, action, initialAction);
    observeCallback();
    expect(initialAction).not.toHaveBeenCalled();
    jest.advanceTimersByTime(200);
    expect(initialAction).toHaveBeenCalled();
    expect(action).not.toHaveBeenCalled();
  });
  it("calls action on subsequent resizes after delay", function () {
    var action = jest.fn();
    var initialAction = jest.fn();
    (0, _["default"])(mockElement, action, initialAction);
    observeCallback();
    jest.advanceTimersByTime(200);
    observeCallback();
    expect(action).not.toHaveBeenCalled();
    jest.advanceTimersByTime(200);
    expect(action).toHaveBeenCalled();
    expect(initialAction).toHaveBeenCalledTimes(1);
  });
  it("debounces rapid resize events", function () {
    var action = jest.fn();
    (0, _["default"])(mockElement, action);
    observeCallback();
    jest.advanceTimersByTime(200);
    observeCallback();
    observeCallback();
    observeCallback();
    jest.advanceTimersByTime(100);
    expect(action).not.toHaveBeenCalled();
    jest.advanceTimersByTime(200);
    expect(action).toHaveBeenCalledTimes(1);
  });
  it("handles missing initialAction", function () {
    var action = jest.fn();
    (0, _["default"])(mockElement, action);
    observeCallback();
    jest.advanceTimersByTime(200);
    expect(action).not.toHaveBeenCalled();
  });
  it("returns cleanup function that disconnects observer", function () {
    var action = jest.fn();
    var cleanup = (0, _["default"])(mockElement, action);
    cleanup();
    expect(mockObserver.disconnect).toHaveBeenCalled();
  });
  it("clears pending timeouts on cleanup", function () {
    var action = jest.fn();
    var cleanup = (0, _["default"])(mockElement, action);
    observeCallback();
    cleanup();
    jest.advanceTimersByTime(300);
    expect(action).not.toHaveBeenCalled();
  });
});