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自定义选择器引擎

¥Custom selector engines

Playwright 支持自定义选择器引擎，已在 selectors.register() 注册。

¥Playwright supports custom selector engines, registered with selectors.register().

选择器引擎应具有以下属性：

¥Selector engine should have the following properties:

query 函数查询相对于 root 匹配 selector 的第一个元素。

¥query function to query first element matching selector relative to the root.
queryAll 函数查询相对于 root 匹配 selector 的所有元素。

¥queryAll function to query all elements matching selector relative to the root.

默认情况下，引擎直接在框架的 JavaScript 上下文中运行，例如，可以调用应用定义的函数。要将引擎与框架中的任何 JavaScript 隔离，但保留对 DOM 的访问权限，请使用 {contentScript: true} 选项注册引擎。内容脚本引擎更安全，因为它可以防止对全局对象的任何篡改，例如更改 Node.prototype 方法。所有内置选择器引擎都作为内容脚本运行。请注意，当引擎与其他自定义引擎一起使用时，不能保证作为内容脚本运行。

¥By default the engine is run directly in the frame's JavaScript context and, for example, can call an application-defined function. To isolate the engine from any JavaScript in the frame, but leave access to the DOM, register the engine with {contentScript: true} option. Content script engine is safer because it is protected from any tampering with the global objects, for example altering Node.prototype methods. All built-in selector engines run as content scripts. Note that running as a content script is not guaranteed when the engine is used together with other custom engines.

创建页面之前必须注册选择器。

¥Selectors must be registered before creating the page.

注册根据标签名称查询元素的选择器引擎的示例：

¥An example of registering selector engine that queries elements based on a tag name:

baseTest.ts
import { test as base } from '@playwright/test';

export { expect } from '@playwright/test';

// Must be a function that evaluates to a selector engine instance.
const createTagNameEngine = () => ({
  // Returns the first element matching given selector in the root's subtree.
  query(root, selector) {
    return root.querySelector(selector);
  },

  // Returns all elements matching given selector in the root's subtree.
  queryAll(root, selector) {
    return Array.from(root.querySelectorAll(selector));
  }
});

export const test = base.extend<{}, { selectorRegistration: void }>({
  // Register selectors once per worker.
  selectorRegistration: [async ({ playwright }, use) => {
    // Register the engine. Selectors will be prefixed with "tag=".
    await playwright.selectors.register('tag', createTagNameEngine);
    await use();
  }, { scope: 'worker', auto: true }],
});

example.spec.ts
import { test, expect } from './baseTest';

test('selector engine test', async ({ page }) => {
  // Now we can use 'tag=' selectors.
  const button = page.locator('tag=button');
  await button.click();

  // We can combine it with built-in locators.
  await page.locator('tag=div').getByText('Click me').click();

  // We can use it in any methods supporting selectors.
  await expect(page.locator('tag=button')).toHaveCount(3);
});

自定义选择器引擎​

自定义选择器引擎