Interface Coverage

Coverage gathers information about parts of JavaScript and CSS that were used by the page.

An example of using JavaScript coverage to produce Istanbul report for page load:

NOTE Coverage APIs are only supported on Chromium-based browsers.

const { chromium } = require('playwright');
const v8toIstanbul = require('v8-to-istanbul');

(async () => {
  const browser = await chromium.launch();
  const page = await browser.newPage();
  await page.coverage.startJSCoverage();
  await page.goto('https://chromium.org');
  const coverage = await page.coverage.stopJSCoverage();
  for (const entry of coverage) {
    const converter = v8toIstanbul('', 0, { source: entry.source });
    await converter.load();
    converter.applyCoverage(entry.functions);
    console.log(JSON.stringify(converter.toIstanbul()));
  }
  await browser.close();
})();

Hierarchy

Methods

startCSSCoverage startJSCoverage stopCSSCoverage stopJSCoverage

Methods

startCSSCoverage

  • Returns coverage is started

    Parameters

    • Optional options: {
          resetOnNavigation?: boolean;
      }
      Optional
      • Optional resetOnNavigation?: boolean

        Whether to reset coverage on every navigation. Defaults to true.

    Returns Promise<void>

startJSCoverage

  • Returns coverage is started

    NOTE Anonymous scripts are ones that don't have an associated url. These are scripts that are dynamically created on the page using eval or new Function. If reportAnonymousScripts is set to true, anonymous scripts will have __playwright_evaluation_script__ as their URL.

    Parameters

    • Optional options: {
          reportAnonymousScripts?: boolean;
          resetOnNavigation?: boolean;
      }
      Optional
      • Optional reportAnonymousScripts?: boolean

        Whether anonymous scripts generated by the page should be reported. Defaults to false.

      • Optional resetOnNavigation?: boolean

        Whether to reset coverage on every navigation. Defaults to true.

    Returns Promise<void>

stopCSSCoverage

  • Returns the array of coverage reports for all stylesheets

    NOTE CSS Coverage doesn't include dynamically injected style tags without sourceURLs.

    Returns Promise<{
        ranges: {
            end: number;
            start: number;
        }[];
        text?: string;
        url: string;
    }[]>

stopJSCoverage

  • Returns the array of coverage reports for all scripts

    NOTE JavaScript Coverage doesn't include anonymous scripts by default. However, scripts with sourceURLs are reported.

    Returns Promise<{
        functions: {
            functionName: string;
            isBlockCoverage: boolean;
            ranges: {
                count: number;
                endOffset: number;
                startOffset: number;
            }[];
        }[];
        scriptId: string;
        source?: string;
        url: string;
    }[]>

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