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---
id: touch-events
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title: "Emulating legacy touch events"
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---
## Introduction
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Web applications that handle [touch events ](https://developer.mozilla.org/en-US/docs/Web/API/Touch_events ) to respond to gestures like swipe, pinch, and tap can be tested by manually dispatching [TouchEvent ](https://developer.mozilla.org/en-US/docs/Web/API/TouchEvent/TouchEvent )s to the page. The examples below demonstrate how to use [`method: Locator.dispatchEvent`] and pass [Touch ](https://developer.mozilla.org/en-US/docs/Web/API/Touch ) points as arguments.
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### Emulating pan gesture
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In the example below, we emulate pan gesture that is expected to move the map. The app under test only uses `clientX/clientY` coordinates of the touch point, so we initialize just that. In a more complex scenario you may need to also set `pageX/pageY/screenX/screenY` , if your app needs them.
```js
import { test, expect, devices, type Locator } from '@playwright/test';
test.use({ ...devices['Pixel 7'] });
async function pan(locator: Locator, deltaX?: number, deltaY?: number, steps?: number) {
const { centerX, centerY } = await locator.evaluate((target: HTMLElement) => {
const bounds = target.getBoundingClientRect();
const centerX = bounds.left + bounds.width / 2;
const centerY = bounds.top + bounds.height / 2;
return { centerX, centerY };
});
// Providing only clientX and clientY as the app only cares about those.
const touches = [{
identifier: 0,
clientX: centerX,
clientY: centerY,
}];
await locator.dispatchEvent('touchstart',
{ touches, changedTouches: touches, targetTouches: touches });
steps = steps ?? 5;
deltaX = deltaX ?? 0;
deltaY = deltaY ?? 0;
for (let i = 1; i < = steps; i++) {
const touches = [{
identifier: 0,
clientX: centerX + deltaX * i / steps,
clientY: centerY + deltaY * i / steps,
}];
await locator.dispatchEvent('touchmove',
{ touches, changedTouches: touches, targetTouches: touches });
}
await locator.dispatchEvent('touchend');
}
test(`pan gesture to move the map`, async ({ page }) => {
await page.goto('https://www.google.com/maps/place/@37.4117722,-122.0713234,15z',
{ waitUntil: 'commit' });
await page.getByRole('button', { name: 'Keep using web' }).click();
await expect(page.getByRole('button', { name: 'Keep using web' })).not.toBeVisible();
// Get the map element.
const met = page.locator('[data-test-id="met"]');
for (let i = 0; i < 5 ; i + + )
await pan(met, 200, 100);
// Ensure the map has been moved.
await expect(met).toHaveScreenshot();
});
```
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### Emulating pinch gesture
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In the example below, we emulate pinch gesture, i.e. two touch points moving closer to each other. It is expected to zoom out the map. The app under test only uses `clientX/clientY` coordinates of touch points, so we initialize just that. In a more complex scenario you may need to also set `pageX/pageY/screenX/screenY` , if your app needs them.
```js
import { test, expect, devices, type Locator } from '@playwright/test';
test.use({ ...devices['Pixel 7'] });
async function pinch(locator: Locator,
arg: { deltaX?: number, deltaY?: number, steps?: number, direction?: 'in' | 'out' }) {
const { centerX, centerY } = await locator.evaluate((target: HTMLElement) => {
const bounds = target.getBoundingClientRect();
const centerX = bounds.left + bounds.width / 2;
const centerY = bounds.top + bounds.height / 2;
return { centerX, centerY };
});
const deltaX = arg.deltaX ?? 50;
const steps = arg.steps ?? 5;
const stepDeltaX = deltaX / (steps + 1);
// Two touch points equally distant from the center of the element.
const touches = [
{
identifier: 0,
clientX: centerX - (arg.direction === 'in' ? deltaX : stepDeltaX),
clientY: centerY,
},
{
identifier: 1,
clientX: centerX + (arg.direction === 'in' ? deltaX : stepDeltaX),
clientY: centerY,
},
];
await locator.dispatchEvent('touchstart',
{ touches, changedTouches: touches, targetTouches: touches });
// Move the touch points towards or away from each other.
for (let i = 1; i < = steps; i++) {
const offset = (arg.direction === 'in' ? (deltaX - i * stepDeltaX) : (stepDeltaX * (i + 1)));
const touches = [
{
identifier: 0,
clientX: centerX - offset,
clientY: centerY,
},
{
identifier: 0,
clientX: centerX + offset,
clientY: centerY,
},
];
await locator.dispatchEvent('touchmove',
{ touches, changedTouches: touches, targetTouches: touches });
}
await locator.dispatchEvent('touchend', { touches: [], changedTouches: [], targetTouches: [] });
}
test(`pinch in gesture to zoom out the map`, async ({ page }) => {
await page.goto('https://www.google.com/maps/place/@37.4117722,-122.0713234,15z',
{ waitUntil: 'commit' });
await page.getByRole('button', { name: 'Keep using web' }).click();
await expect(page.getByRole('button', { name: 'Keep using web' })).not.toBeVisible();
// Get the map element.
const met = page.locator('[data-test-id="met"]');
for (let i = 0; i < 5 ; i + + )
await pinch(met, { deltaX: 40, direction: 'in' });
// Ensure the map has been zoomed out.
await expect(met).toHaveScreenshot();
});
```