Using Jest with Puppeteer : Evaluation failed: ReferenceError: cov_4kq3tptqc is not defined

Question

I'm trying to get description of a page with Puppeteer, I have a high order function that provides the page object to this function :

export const checkDescription = async page => {
  const metaDescription = await page.$eval(
    'meta[name="description"]',
    description => description.getAttribute("content")
  );
  return metaDescription;
};

the function works as expected. Then, I'm using Jest to run a test.

const testDescription = await withPage(checkDescription)(URL);
expect(typeof testDescription).toBe("string");

I have the following err:

  Error: Evaluation failed: ReferenceError: cov_4kq3tptqc is not defined
      at __puppeteer_evaluation_script__:2:41
      at ExecutionContext.evaluateHandle 
      at <anonymous>
      at process._tickCallback (internal/process/next_tick.js:188:7)
    -- ASYNC --
      at ExecutionContext.<anonymous> 
      at ExecutionContext.evaluate
      at ExecutionContext.<anonymous> 
      at ElementHandle.$eval
      at <anonymous>
      at process._tickCallback (internal/process/next_tick.js:188:7)
    -- ASYNC --

If I just paste the function in the jest file, then it works as expected

I had the same issue using Playwright with Jest. @oneralon's answer solved it for me. — Peter Bagnall, Jun 08 '21 at 16:53

score 9 · Answer 1 · answered May 06 '20 at 05:23

9

If you need to collect the coverage, it can be fixed by adding /* istanbul ignore next */ before browser contexted functions (lines with .eval) to prevent istanbul coverage injects.

answered May 06 '20 at 05:23

oneralon

91
1
1

The relevant discussion at Istanbul's GitHub: https://github.com/istanbuljs/nyc/issues/514 – theDavidBarton Apr 06 '21 at 10:18
I had the same problem with playwright, and perhaps not surprisingly, this fixed the issue there too. – Peter Bagnall Jun 08 '21 at 16:28

score 6 · Answer 2 · answered Mar 25 '19 at 14:52

6

In puppeteer, while running tests, istanbul was inserting the following :

 /* istanbul ignore next */cov_4kq3tptqc.f[7]++;
                    cov_4kq3tptqc.s[19]++;

Was fixed by adding config.collectCoverage = false; to the jest.config

answered Mar 25 '19 at 14:52

Elena

569
3
7
19

Not only does `config.collectCoverage = false` fixes break the above error but also the breakpoint of vscode in debugging mode (typescript) now works when – fredtma Mar 10 '20 at 11:41

Using Jest with Puppeteer : Evaluation failed: ReferenceError: cov_4kq3tptqc is not defined

2 Answers2

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