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/* eslint-disable class-methods-use-this, max-classes-per-file */
import { isMatch } from 'lodash';
/**
* This class gives us a JSDom friendly DOM observer which we can manually trigger in tests
*
* Use this in place of MutationObserver or IntersectionObserver
*/
class MockObserver {
constructor(cb) {
this.$_cb = cb;
this.$_observers = [];
}
observe(node, options = {}) {
this.$_observers.push([node, options]);
}
disconnect() {
this.$_observers = [];
}
takeRecords() {}
// eslint-disable-next-line camelcase
$_triggerObserve(node, { entry = {}, options = {} } = {}) {
if (this.$_hasObserver(node, options)) {
this.$_cb([{ target: node, ...entry }]);
}
}
// eslint-disable-next-line camelcase
$_hasObserver(node, options = {}) {
return this.$_observers.some(
([obvNode, obvOptions]) => node === obvNode && isMatch(options, obvOptions),
);
}
}
class MockIntersectionObserver extends MockObserver {
unobserve(node) {
this.$_observers = this.$_observers.filter(([obvNode]) => node === obvNode);
}
}
/**
* Use this function to setup a mock observer instance in place of the given DOM Observer
*
* Example:
* ```
* describe('', () => {
* const { trigger: triggerMutate } = useMockMutationObserver();
*
* it('test', () => {
* triggerMutate(el, { options: { childList: true }, entry: { } });
* });
* })
* ```
*
* @param {String} key
*/
const useMockObserver = (key, createMock) => {
let mockObservers = [];
let origObserver;
beforeEach(() => {
origObserver = global[key];
global[key] = jest.fn().mockImplementation((...args) => {
const mockObserver = createMock(...args);
mockObservers.push(mockObserver);
return mockObserver;
});
});
afterEach(() => {
mockObservers.forEach((x) => x.disconnect());
mockObservers = [];
global[key] = origObserver;
});
const trigger = (...args) => {
mockObservers.forEach((observer) => {
observer.$_triggerObserve(...args);
});
};
return { trigger };
};
export const useMockIntersectionObserver = () =>
useMockObserver('IntersectionObserver', (...args) => new MockIntersectionObserver(...args));
export const useMockMutationObserver = () =>
useMockObserver('MutationObserver', (...args) => new MockObserver(...args));
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