Worker
The Worker class represents a WebWorker.
worker
event is emitted on the page object to signal a worker creation.
close
event is emitted on the worker object when the worker is gone.
- event: 'close'
- worker.evaluate(pageFunction[, arg])
- worker.evaluateHandle(pageFunction[, arg])
- worker.url()
#
event: 'close'- <Worker>
Emitted when this dedicated WebWorker is terminated.
#
worker.evaluate(pageFunction[, arg])pageFunction
<function|string> Function to be evaluated in the worker contextarg
<EvaluationArgument> Optional argument to pass topageFunction
- returns: <Promise<Serializable>> Promise which resolves to the return value of
pageFunction
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.
#
worker.evaluateHandle(pageFunction[, arg])pageFunction
<function|string> Function to be evaluated in the page contextarg
<EvaluationArgument> Optional argument to pass topageFunction
- returns: <Promise<JSHandle>> Promise which resolves to the return value of
pageFunction
as in-page object (JSHandle)
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.
#
worker.url()- returns: <string>