docs/api/puppeteer.webworker.evaluate.md
Evaluates a given function in the worker.
class WebWorker {
evaluate<
Params extends unknown[],
Func extends EvaluateFunc<Params> = EvaluateFunc<Params>,
>(func: Func | string, ...args: Params): Promise<Awaited<ReturnType<Func>>>;
}
Parameter
</th><th>Type
</th><th>Description
</th></tr></thead> <tbody><tr><td>func
</td><td>Func | string
</td><td>Function to be evaluated.
</td></tr> <tr><td>args
</td><td>Params
</td><td>Arguments to pass into func.
Returns:
Promise<Awaited<ReturnType<Func>>>
The result of func.
If the given function returns a promise, evaluate will wait for the promise to resolve.
As a rule of thumb, if the return value of the given function is more complicated than a JSON object (e.g. most classes), then evaluate will _likely_ return some truncated value (or {}). This is because we are not returning the actual return value, but a deserialized version as a result of transferring the return value through a protocol to Puppeteer.
In general, you should use evaluateHandle if evaluate cannot serialize the return value properly or you need a mutable handle to the return object.