Start JavaScript coverage on a Puppeteer Page before navigating to the page or performing the interactions you want to measure, then call stopJSCoverage() to get the script entries. For most single-page captures, the defaults are suitable; configure options when you need function-level data, anonymous scripts, or raw V8 coverage.
Configure and collect JavaScript coverage
This complete example starts coverage before navigation, exercises the page, retrieves the entries, and closes the browser even if a step fails:
import puppeteer from 'puppeteer';
const browser = await puppeteer.launch();
try {
const page = await browser.newPage();
await page.coverage.startJSCoverage({
resetOnNavigation: true,
reportAnonymousScripts: false,
includeRawScriptCoverage: false,
useBlockCoverage: true,
});
await page.goto('https://example.com');
// Perform the interactions whose JavaScript execution you want to measure.
const entries = await page.coverage.stopJSCoverage();
console.log(`Collected coverage for ${entries.length} scripts`);
// Process entries or pass them to an Istanbul conversion tool.
} finally {
await browser.close();
}The options shown are the documented defaults. If you want those defaults, you can start collection with await page.coverage.startJSCoverage(). Coverage is scoped to the page: start it before the activity of interest and stop it afterward. The stop call returns an array of script entries. See the Puppeteer startJSCoverage() reference and stopJSCoverage() reference.
Choose the coverage options you need
Puppeteer documents four JavaScript coverage options. Their defaults and effects are:
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
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| Option | Default | Effect |
|---|---|---|
useBlockCoverage |
true |
Collect block-level coverage. Set to false for function-level collection. |
reportAnonymousScripts |
false |
Include dynamically created scripts that have no URL when enabled. |
includeRawScriptCoverage |
false |
Include the raw V8 protocol script coverage object on entries when enabled. |
resetOnNavigation |
true |
Reset coverage on navigation by default. |
These values are documented in Puppeteer’s JSCoverageOptions reference and the startJSCoverage() method reference. Check the documentation and types for your installed Puppeteer release before relying on a version-specific API.
Block-level or function-level data
Keep useBlockCoverage: true when you want block-level execution detail; choose false when function-level collection is sufficient. The appropriate granularity depends on what your report needs to show.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
Anonymous scripts created at runtime
By default, anonymous scripts are excluded. Enable reportAnonymousScripts: true when dynamically generated code matters to your measurement. This includes scripts created with eval or new Function. Such entries generally have a URL beginning with debugger://VM, unless the script supplies a //# sourceURL comment. Scripts with source URLs are reported. See the method reference and stop method reference.
Raw V8 coverage
Set includeRawScriptCoverage: true if you need the underlying V8 script coverage data in addition to the usual entry fields. Leave it off if your processing only needs the script text and ranges.
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
Why is coverage empty after navigation?
Coverage should be started before navigation if you want to include scripts executed during page load. Also, do not assume that setting resetOnNavigation: false preserves data from the document you are leaving: Chrome may discard that document’s JavaScript execution environment and coverage data during navigation. Puppeteer’s documented approach for collecting across documents is to stop coverage before navigating away, start a new collection for the next page, and merge the resulting reports. See the JSCoverageOptions reference.
- Start coverage on the current page.
- Run the navigation and interactions you want counted.
- Call
stopJSCoverage()before leaving that document and retain the returned entries. - Navigate to the next document, start coverage again, and collect its entries separately.
- Merge the reports in your reporting workflow.
Read the entries and export a report
Each returned entry represents a JavaScript script and includes coverage ranges. When requested, it can also include rawScriptCoverage, typed as the V8 protocol script coverage object. Puppeteer’s API reference demonstrates byte-based coverage by adding each script’s text.length and the used ranges, calculated as range.end - range.start - 1, then dividing used bytes by total bytes. That is one possible byte-coverage calculation, not a universal measure of test quality or application behavior. See the Coverage class reference and the JSCoverageEntry reference.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
For Istanbul-compatible output, Puppeteer points to the separate puppeteer-to-istanbul package. Stopping coverage gives you Puppeteer’s entries; conversion to Istanbul format is a distinct step.
Troubleshoot common coverage issues
- No scripts or missing page-load coverage: Collection may have started after navigation. Start it before
page.goto()or whichever activity should be counted. - Anonymous runtime code is absent: Enable
reportAnonymousScripts. Scripts with no URL are excluded by default; scripts with asourceURLare reported. - Coverage appears to disappear on navigation: Do not rely on
resetOnNavigation: falseto preserve the previous document’s data. Stop before navigating, restart on the next document, and merge the reports. - You need an Istanbul report: The Puppeteer entries are not themselves an Istanbul export. Use the separately identified
puppeteer-to-istanbulconverter. - Your API or option types differ: The API references surfaced for Puppeteer versions 25.5.0 through 25.12.0. Confirm the method and option definitions against the documentation for the version installed in your project.
Or skip the browser setup
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- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
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