8054bac046
Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>
119 lines
3.4 KiB
Markdown
119 lines
3.4 KiB
Markdown
# Query Selectors
|
|
|
|
Queries are the primary mechanism for interacting with the DOM on your site. For example, a typical workflow goes like:
|
|
|
|
```ts
|
|
// Import puppeteer
|
|
import puppeteer from 'puppeteer';
|
|
|
|
(async () => {
|
|
// Launch the browser
|
|
const browser = await puppeteer.launch();
|
|
|
|
// Create a page
|
|
const page = await browser.newPage();
|
|
|
|
// Go to your site
|
|
await page.goto('YOUR_SITE');
|
|
|
|
// Query for an element handle.
|
|
const element = await page.waitForSelector('div > .class-name');
|
|
|
|
// Do something with element...
|
|
await element.click(); // Just an example.
|
|
|
|
// Dispose of handle
|
|
await element.dispose();
|
|
|
|
// Close browser.
|
|
await browser.close();
|
|
})();
|
|
```
|
|
|
|
## CSS
|
|
|
|
CSS selectors follow the CSS spec of the browser being automated. We provide some basic type deduction for CSS selectors (such as `HTMLInputElement` for `input`), but any selector that contains no type information (such as `.class-name`) will need to be coerced manually using TypeScript's `as` coercion mechanism.
|
|
|
|
### Example
|
|
|
|
```ts
|
|
// Automatic
|
|
const element = await page.waitForSelector('div > input');
|
|
// Manual
|
|
const element = (await page.waitForSelector(
|
|
'div > .class-name-for-input'
|
|
)) as HTMLInputElement;
|
|
```
|
|
|
|
## Built-in selectors
|
|
|
|
Built-in selectors are Puppeteer's own class of selectors for doing things CSS cannot. Every built-in selector starts with a prefix `.../` to assist Puppeteer in distinguishing between CSS selectors and a built-in.
|
|
|
|
### Text selectors (`text/`)
|
|
|
|
Text selectors will select "minimal" elements containing the given text, even within (open) shadow roots. Here, "minimum" means the deepest elements that contain a given text, but not their parents (which technically will also contain the given text).
|
|
|
|
#### Example
|
|
|
|
```ts
|
|
// Note we usually need type coercion since the type cannot be deduced, but for text selectors, `instanceof` checks may be better for runtime validation.
|
|
const element = await page.waitForSelector('text/My name is Jun');
|
|
```
|
|
|
|
### XPath selectors (`xpath/`)
|
|
|
|
XPath selectors will use the browser's native [`Document.evaluate`](https://developer.mozilla.org/en-US/docs/Web/API/Document/evaluate) to query for elements.
|
|
|
|
#### Example
|
|
|
|
```ts
|
|
// There is not type deduction for XPaths.
|
|
const node = await page.waitForSelector('xpath/h2');
|
|
```
|
|
|
|
### ARIA selectors (`aria/`)
|
|
|
|
ARIA selectors can be used to find elements with a given ARIA label. These labels are computed using Chrome's internal representation.
|
|
|
|
#### Example
|
|
|
|
```ts
|
|
const node = await page.waitForSelector('aria/Button name');
|
|
```
|
|
|
|
### Pierce selectors (`pierce/`)
|
|
|
|
Pierce selectors will run the `querySelector*` API on the document and all shadow roots to find an element.
|
|
|
|
:::danger
|
|
|
|
Selectors will **not** _partially_ pierce through shadow roots. See the examples below.
|
|
|
|
:::
|
|
|
|
#### Example
|
|
|
|
Suppose the HTML is
|
|
|
|
```html
|
|
<div>
|
|
<custom-element>
|
|
<div></div>
|
|
</custom-element>
|
|
</div>
|
|
```
|
|
|
|
Then
|
|
|
|
```ts
|
|
// This will be two elements because of the outer and inner div.
|
|
expect((await page.$$('pierce/div')).length).toBe(2);
|
|
|
|
// Partial piercing doesn't work.
|
|
expect((await page.$$('pierce/div div')).length).toBe(0);
|
|
```
|
|
|
|
## Custom selectors
|
|
|
|
Puppeteer provides users the ability to add their own query selectors to Puppeteer using [Puppeteer.registerCustomQueryHandler](../api/puppeteer.registercustomqueryhandler.md). This is useful for creating custom selectors based on framework objects or other vendor-specific objects.
|