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Version: 1.12.0

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 = new v8toIstanbul('', 0, { source: entry.source });
await converter.load();
converter.applyCoverage(entry.functions);
console.log(JSON.stringify(converter.toIstanbul()));
}
await browser.close();
})();

coverage.startCSSCoverage([options])#

  • options <Object>
    • resetOnNavigation <boolean> Whether to reset coverage on every navigation. Defaults to true.
  • returns: <Promise<void>>

Returns coverage is started

coverage.startJSCoverage([options])#

  • options <Object>
    • reportAnonymousScripts <boolean> Whether anonymous scripts generated by the page should be reported. Defaults to false.
    • resetOnNavigation <boolean> Whether to reset coverage on every navigation. Defaults to true.
  • returns: <Promise<void>>

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.

coverage.stopCSSCoverage()#

  • returns: <Promise<Array<Object>>>
    • url <string> StyleSheet URL
    • text <string> StyleSheet content, if available.
    • ranges <Array<Object>> StyleSheet ranges that were used. Ranges are sorted and non-overlapping.
      • start <number> A start offset in text, inclusive
      • end <number> An end offset in text, exclusive

Returns the array of coverage reports for all stylesheets

note

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

coverage.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.