2.4 KiB
2.4 KiB
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| WebWorker |
WebWorker class
The WebWorker class represents a WebWorker.
Signature:
export declare class WebWorker extends EventEmitter
Extends: EventEmitter
Remarks
The events workercreated and workerdestroyed are emitted on the page object to signal the worker lifecycle.
The constructor for this class is marked as internal. Third-party code should not call the constructor directly or create subclasses that extend the WebWorker class.
Example
page.on('workercreated', worker => console.log('Worker created: ' + worker.url()));
page.on('workerdestroyed', worker => console.log('Worker destroyed: ' + worker.url()));
console.log('Current workers:');
for (const worker of page.workers()) {
console.log(' ' + worker.url());
}
Methods
| Method | Modifiers | Description |
|---|---|---|
| evaluate(pageFunction, args) | If the function passed to the worker.evaluate returns a Promise, then worker.evaluate would wait for the promise to resolve and return its value. If the function passed to the worker.evaluate returns a non-serializable value, then worker.evaluate resolves to undefined. DevTools Protocol also supports transferring some additional values that are not serializable by JSON: -0, NaN, Infinity, -Infinity, and bigint literals. Shortcut for await worker.executionContext()).evaluate(pageFunction, ...args). |
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| evaluateHandle(pageFunction, args) | The only difference between worker.evaluate and worker.evaluateHandle is that worker.evaluateHandle returns in-page object (JSHandle). If the function passed to the worker.evaluateHandle returns a Promise, then worker.evaluateHandle would wait for the promise to resolve and return its value. Shortcut for await worker.executionContext()).evaluateHandle(pageFunction, ...args) |
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| executionContext() | Returns the ExecutionContext the WebWorker runs in | |
| url() |