td-has-headers takes 30+ seconds

[patrickhulce]

1. Open https://www.guidetoonlineschools.com/online-schools
2. Add axe 3.0.2 to the page (https://cdnjs.cloudflare.com/ajax/libs/axe-core/3.0.2/axe.js)
3. Run td-has-headers rule in console

await window.axe.run(document, {
  elementRef: true,
  runOnly: {
    type: 'rule',
    values: ['td-has-header'],
  },
  resultTypes: ['violations', 'inapplicable'],
})

4. Wait...

Seems like you might want to memoize toGrid or something, O(w^2*h^2) is rough :)

axe-core/lib/commons/table/get-headers.js

Line 17 in cd1e5ee

var tableGrid = commons.table.toGrid(commons.dom.findUp(cell, 'table'));

Originally reported in GoogleChrome/lighthouse#5249, Lighthouse axe run never completes within 60s

axe-core version: 3.0.2
chrome version: 66.0.3359.181

[paulirish]

http://giveawaylisting.com/ takes over 3 minutes due to this issue.

[ggennrich]

Any update on this issue? We have a single page on our website that breaks due to this issue. Could someone explain in detail what exactly is breaking in lighthouse so that I have a better idea of what's going on? The fact this breaks on just one of our pages leads me to believe there is something unusual on the page. I'm worried this may be impacting our rankings as we noticed some drops in the last couple months.

[WilcoFiers]

I'm not aware of anyone working on this issue. If you've got some time, we'd very much welcome some suggestions on how to improve the performance. A pull request would also be fantastic. Marking this as help wanted, as I don't see us prioritising this issue any time soon.

[padmavemulapati]

Not taking more than 2seconds for me, verified for axe-core:3.0.3 and chrome 78 version