89 lines
2.4 KiB
JavaScript
89 lines
2.4 KiB
JavaScript
import { addClassIfElementExists, canScrollUp, canScrollDown } from '~/lib/utils/dom_utils';
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const TEST_MARGIN = 5;
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describe('DOM Utils', () => {
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describe('addClassIfElementExists', () => {
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const className = 'biology';
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const fixture = `
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<div class="parent">
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<div class="child"></div>
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</div>
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`;
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let parentElement;
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beforeEach(() => {
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setFixtures(fixture);
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parentElement = document.querySelector('.parent');
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});
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it('adds class if element exists', () => {
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const childElement = parentElement.querySelector('.child');
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expect(childElement).not.toBe(null);
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addClassIfElementExists(childElement, className);
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expect(childElement.classList).toContain(className);
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});
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it('does not throw if element does not exist', () => {
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const childElement = parentElement.querySelector('.other-child');
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expect(childElement).toBe(null);
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addClassIfElementExists(childElement, className);
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});
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});
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describe('canScrollUp', () => {
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[1, 100].forEach(scrollTop => {
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it(`is true if scrollTop is > 0 (${scrollTop})`, () => {
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expect(canScrollUp({ scrollTop })).toBe(true);
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});
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});
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[0, -10].forEach(scrollTop => {
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it(`is false if scrollTop is <= 0 (${scrollTop})`, () => {
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expect(canScrollUp({ scrollTop })).toBe(false);
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});
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});
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it('is true if scrollTop is > margin', () => {
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expect(canScrollUp({ scrollTop: TEST_MARGIN + 1 }, TEST_MARGIN)).toBe(true);
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});
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it('is false if scrollTop is <= margin', () => {
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expect(canScrollUp({ scrollTop: TEST_MARGIN }, TEST_MARGIN)).toBe(false);
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});
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});
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describe('canScrollDown', () => {
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let element;
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beforeEach(() => {
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element = { scrollTop: 7, offsetHeight: 22, scrollHeight: 30 };
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});
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it('is true if element can be scrolled down', () => {
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expect(canScrollDown(element)).toBe(true);
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});
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it('is false if element cannot be scrolled down', () => {
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element.scrollHeight -= 1;
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expect(canScrollDown(element)).toBe(false);
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});
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it('is true if element can be scrolled down, with margin given', () => {
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element.scrollHeight += TEST_MARGIN;
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expect(canScrollDown(element, TEST_MARGIN)).toBe(true);
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});
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it('is false if element cannot be scrolled down, with margin given', () => {
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expect(canScrollDown(element, TEST_MARGIN)).toBe(false);
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});
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});
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});
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