fix: should prefix ShadowRoot with window.

[haoqunjiang]

Otherwise this expression would throw in environments that do not
support ShadowRoot, including the common mocha testing environment
setup that uses jsdom and jsdom-global.

It is because ShadowRoot is not an enumerable property on window,
jsdom-global fails to expose it on the global object.

See the error message at https://app.circleci.com/pipelines/github/vuejs/vue-cli/779/workflows/17d7d7c4-7605-4588-878a-ddb3a6d37102/jobs/24147

[mattelen]

Hi everyone, any thoughts on when this will be merged in master? Quite keen for this bugfix. TIA

[jjdive]

Hi everyone!

I'm running into an error related to this when trying to run a simple test using typescript. I've come up with a minimum repo to reproduce this case at https://github.com/jjdive/vite-vue-ts-tests-error. Anyways, this is the error i get and it points to if (container instanceof window.ShadowRoot && at normalizeContainer (node_modules/@vue/runtime-dom/dist/runtime-dom.cjs.js:1288:19).

Thanks in advance for any help with this!

[haoqunjiang]

@jjdive I'm on my phone so I can't test it. But here's my guess:
It's because your jest version is outdated. Jest 24 uses jsdom v11 by default https://github.com/facebook/jest/blob/v24.0.0/packages/jest-environment-jsdom/package.json#L14 But Shadow DOM support was added in jsdom v12 jsdom/jsdom#2347

[haoqunjiang]

You can either update your jest version or change the configuration to use a different testEnvironment, like what we do in Vue CLI v4 https://github.com/vuejs/vue-cli/blob/b0de229e78ae860c6ebc1e53f4bb481d7549cde7/packages/%40vue/cli-plugin-unit-jest/presets/default/jest-preset.js#L21

[jjdive]

@sodatea, you're totally right! vue-jest@5 is asking for ts-jest@24 (as per 5.0.0-alpha.7) which in turn requires jest@24, so i had to update with:

npm i -D jest@26 --legacy-peer-deps

and the sample test runs without issues (i know this might lead to errors at some point so i'll be looking forward to any vue-jest and the other deps updates).

Thank you very much for pointing me to the right dep update needed!