Support gatherer options, exclude css selectors in axe

[stepet80]

How can we exclude certain elements from the lighthouse cli run. In axe we can do the following where certain elements are excluded based on css selectors:

axe.run(
{
    exclude: [['.exclude1'], ['.exclude2']]
},
(err, results) => {
    // ...
});

[patrickhulce]

Thanks for filing! This isn't currently possible out of the box. You'd need to manually create a custom config and a copy of the accessibility gatherer to run axe with custom arguments yourself. #2087 is one step into making this more a reality with the ability to pass gatherer options, but we're a ways off from that at the moment.

[mohanraj-r]

@patrickhulce Would this be specific to the Accessibility gatherer ? I have more knowledge of that and might be able to work on adding support for passing in the axe config to the gatherer. It could be part of the lighthouse/configuration as a separate GathererConfig section

module.exports = {
  extends: 'lighthouse:default',
  settings: {
    gathererConfig: {
         Accessibility: {
               // axe config overrides
         },
    },
  },
};

But I could also see this being extended to other Gatherers - which would be nice to have I guess. But I have no knowledge of other Gatherers and won't be able to contribute towards that. Maybe that can be a separate effort (by someone else) after adding config override ability to the Accessibility Gatherer?

[patrickhulce]

Thanks for the offer @mohanraj-r! We would want to make gatherer options be available to all gatherers but don't need to necessarily update any other gatherer to take advantage of them yet. We've implemented the early steps to make this happen before but they never landed.

Essentially we want to be able to define options alongside a gatherer, like can be done with audit options today. It would look something like the below

module.exports = {
  extends: 'lighthouse:default',
  passes: [
    {
      passName: 'defaultPass', 
      gatherers: [{id: 'custom-axe', path: 'Accessibility', options: {/* ... */}}],
    }
  ],
  audits: [
    {id: 'custom-axe-audit', path: 'path/to/custom/audit.js'}
  ]
}

[EmmanuelDemey]

Hi,

I double check this morning, I found this options property in the Gatherer configuration.

But I do not know how to get this options inside my Gatherer Implementation.

@patrickhulce how do you retrieve this options inside your custom-axe gatherer ?