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Worker

Worker 类代表 WebWorker。worker 事件在页面对象上触发，以指示工作线程创建。当工作线程消失时，工作线程对象上会触发 close 事件。

¥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.

page.Worker += (_, worker) =>
{
    Console.WriteLine($"Worker created: {worker.Url}");
    worker.Close += (_, _) => Console.WriteLine($"Worker closed {worker.Url}");
};

Console.WriteLine("Current Workers:");
foreach(var pageWorker in page.Workers)
{
    Console.WriteLine($"\tWorker: {pageWorker.Url}");
}

方法​

¥Methods

EvaluateAsync​

Added before v1.9 worker.EvaluateAsync

返回 expression 的返回值。

¥Returns the return value of expression.

如果传递给 Worker.EvaluateAsync() 的函数返回 Promise，那么 Worker.EvaluateAsync() 将等待 Promise 解析并返回其值。

¥If the function passed to the Worker.EvaluateAsync() returns a Promise, then Worker.EvaluateAsync() would wait for the promise to resolve and return its value.

如果传递给 Worker.EvaluateAsync() 的函数返回非 可串行化 值，则 Worker.EvaluateAsync() 返回 undefined。Playwright 还支持传输一些 JSON 无法序列化的附加值：-0、NaN、Infinity、-Infinity。

¥If the function passed to the Worker.EvaluateAsync() returns a non-Serializable value, then Worker.EvaluateAsync() returns undefined. Playwright also supports transferring some additional values that are not serializable by JSON: -0, NaN, Infinity, -Infinity.

用法

¥Usage

await Worker.EvaluateAsync(expression, arg);

参数

¥Arguments

要在浏览器上下文中执行的 JavaScript 表达式。如果表达式的计算结果为函数，则会自动调用该函数。

¥JavaScript expression to be evaluated in the browser context. If the expression evaluates to a function, the function is automatically invoked.

传递给 expression 的可选参数。

¥Optional argument to pass to expression.

返回

¥Returns

  • [object]#

EvaluateHandleAsync​

Added before v1.9 worker.EvaluateHandleAsync

将 expression 的返回值作为 JSHandle 返回。

¥Returns the return value of expression as a JSHandle.

Worker.EvaluateAsync() 和 Worker.EvaluateHandleAsync() 之间的唯一区别是 Worker.EvaluateHandleAsync() 返回 JSHandle。

¥The only difference between Worker.EvaluateAsync() and Worker.EvaluateHandleAsync() is that Worker.EvaluateHandleAsync() returns JSHandle.

如果传递给 Worker.EvaluateHandleAsync() 的函数返回 Promise，那么 Worker.EvaluateHandleAsync() 将等待 Promise 解析并返回其值。

¥If the function passed to the Worker.EvaluateHandleAsync() returns a Promise, then Worker.EvaluateHandleAsync() would wait for the promise to resolve and return its value.

用法

¥Usage

await Worker.EvaluateHandleAsync(expression, arg);

参数

¥Arguments

要在浏览器上下文中执行的 JavaScript 表达式。如果表达式的计算结果为函数，则会自动调用该函数。

¥JavaScript expression to be evaluated in the browser context. If the expression evaluates to a function, the function is automatically invoked.

传递给 expression 的可选参数。

¥Optional argument to pass to expression.

返回

¥Returns

URL​

Added before v1.9 worker.Url

用法

¥Usage

Worker.Url

返回

¥Returns

事件​

¥Events

事件 Close​

¥event Close

Added before v1.9 worker.event Close

当该专用 WebWorker 终止时触发。

¥Emitted when this dedicated WebWorker is terminated.

用法

¥Usage

Worker.Close += async (_, worker) => {};

事件数据

¥Event data