waitForEvent(event[, optionsOrPredicate])
Documentation
Grafana k6
JavaScript API
k6/browser
BrowserContext
waitForEvent(event[, optionsOrPredicate])
Open source
Waits for the event to fire and returns its value. If a predicate function has been set it will pass the value to the predicate function, which must return true
for the promise to resolve.
Parameter | Type | Default | Description |
---|---|---|---|
event | string | null | Name of event to wait for. Currently the 'page' event is the only one that is supported. |
optionsOrPredicate | function|object | null | Optional. If it’s a function, the 'page' event data will be passed to it and it must return true to continue. |
optionsOrPredicate.predicate | function | null | Optional. Function that will be called when the 'page' event is emitted. The event data will be passed to it and it must return true to continue. |
optionsOrPredicate.timeout | number | 30000 | Optional. Maximum time to wait in milliseconds. |
Returns
Type | Description |
---|---|
Promise<Page> | A Promise that fulfills with a page object when the page event has been emitted. |
Example
This API is useful when you want to wait for the new page to open after clicking on a link that opens in a new tab.
JavaScript
import { browser } from 'k6/browser';
export const options = {
scenarios: {
ui: {
executor: 'shared-iterations',
options: {
browser: {
type: 'chromium',
},
},
},
},
};
export default async function () {
const page = await browser.newPage();
await page.goto('https://test.k6.io/');
await page.keyboard.down('ControlOrMeta');
// Open the link in a new tab with the help of the meta key.
// Wait for the new page to be created.
const browserContext = browser.context();
const [newTab] = await Promise.all([
browserContext.waitForEvent('page'),
await page.locator('a[href="/my_messages.php"]').click(),
]);
await page.keyboard.up('ControlOrMeta');
// Wait for the new page (tab) to load.
await newTab.waitForLoadState('load');
// Take screenshots of each page.
await page.screenshot({ path: `screenshot-page.png` });
await newTab.screenshot({ path: `screenshot-newTab.png` });
await newTab.close();
await page.close();
}
Here’s an example working with the predicate:
JavaScript
import { browser } from 'k6/browser';
export const options = {
scenarios: {
browser: {
executor: 'shared-iterations',
options: {
browser: {
type: 'chromium',
},
},
},
},
};
export default async function () {
const context = await browser.newContext();
// Call waitForEvent with a predicate which will return true once at least
// one page has been created.
let counter = 0;
const promise = await context.waitForEvent('page', {
predicate: (page) => {
if (++counter >= 1) {
return true;
}
return false;
},
});
// Now we create a page.
const page = await context.newPage();
// Wait for the predicate to pass.
await promise;
console.log('predicate passed');
await page.close();
}
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