add mutation observer polyfill for jest test env #20996
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| // https://github.com/aurelia/pal-nodejs/blob/master/src/polyfills/mutation-observer.ts | ||
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| The MIT License (MIT) |
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We are going to need a mutation observer polyfill for the browser too no? Is there a reason we need one for jest specifically? Why not use one from npm?
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A polyfill is not needed for the browser since MutationObservser is implemented in IE 11 and has had support in Firefox, Chrome, and Safari for a long time.
We need a polyfill for jest tests because jsdom does not implement MutationObservser and therefore any tests that render a component using MutationObservser will fail to render.
I was using the MutationObservser polyfill that EUI is using. I will see if an npm version exists that we can use.
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src/dev/jest/setup/polyfills.js
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| // bluebird < 3.5.0 does not work with MutationObserver polyfill | ||
| // when MutationObserver exists, bluebird avoids using node's builtin async schedulers |
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Can you link to docs or something for this?
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There are no docs to link to. @chandlerprall found this while digging around in their code base
src/dev/jest/setup/polyfills.js
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| // bluebird < 3.5.0 does not work with MutationObserver polyfill |
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FWIW, the update that works alongside MutationObserver's polyfill happened in v3.3.5; I don't think that's vital information but wanted to call it out anyway.
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* add mutation observer polyfill for jest test env * use polyfill from npm * set bluebird scheduler * use correct version in comment about bluebird
* add mutation observer polyfill for jest test env * use polyfill from npm * set bluebird scheduler * use correct version in comment about bluebird
EUI 3.1.0 updates the EuiPopover component to use MutationObservser. Any jest tests that uses this component and render with
mountwill fail because jsdom does not implement MutationObservser.This PR sets up a MutationObserver polyfill for the jest runtime environment. A polyfill is not needed for the browser since MutationObservser is implemented in IE 11 and has had support in Firefox, Chrome, and Safari for a long time.
bluebirddoes not play nice with the MutationObserver polyfill.