60 lines
2.6 KiB
Markdown
60 lines
2.6 KiB
Markdown
---
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sidebar_label: Coverage
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---
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# Coverage class
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The Coverage class provides methods to gather information about parts of JavaScript and CSS that were used by the page.
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#### Signature:
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```typescript
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export declare class Coverage
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```
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## Remarks
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To output coverage in a form consumable by [Istanbul](https://github.com/istanbuljs), see [puppeteer-to-istanbul](https://github.com/istanbuljs/puppeteer-to-istanbul).
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## Example
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An example of using JavaScript and CSS coverage to get percentage of initially executed code:
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```ts
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// Enable both JavaScript and CSS coverage
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await Promise.all([
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page.coverage.startJSCoverage(),
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page.coverage.startCSSCoverage(),
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]);
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// Navigate to page
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await page.goto('https://example.com');
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// Disable both JavaScript and CSS coverage
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const [jsCoverage, cssCoverage] = await Promise.all([
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page.coverage.stopJSCoverage(),
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page.coverage.stopCSSCoverage(),
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]);
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let totalBytes = 0;
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let usedBytes = 0;
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const coverage = [...jsCoverage, ...cssCoverage];
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for (const entry of coverage) {
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totalBytes += entry.text.length;
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for (const range of entry.ranges) usedBytes += range.end - range.start - 1;
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}
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console.log(`Bytes used: ${(usedBytes / totalBytes) * 100}%`);
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```
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## Constructors
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| Constructor | Modifiers | Description |
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| -------------------------------------------------------------- | --------- | ------------------------------------------------------------ |
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| [(constructor)(client)](./puppeteer.coverage._constructor_.md) | | Constructs a new instance of the <code>Coverage</code> class |
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## Methods
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| Method | Modifiers | Description |
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| --------------------------------------------------------------------- | --------- | --------------------------------------------------------------------------- |
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| [startCSSCoverage(options)](./puppeteer.coverage.startcsscoverage.md) | | |
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| [startJSCoverage(options)](./puppeteer.coverage.startjscoverage.md) | | |
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| [stopCSSCoverage()](./puppeteer.coverage.stopcsscoverage.md) | | Promise that resolves to the array of coverage reports for all stylesheets. |
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| [stopJSCoverage()](./puppeteer.coverage.stopjscoverage.md) | | Promise that resolves to the array of coverage reports for all scripts. |
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