Add WebIDL typedefs by json

[saschanaz]

This is a subset of #300.

This fixes some unexpected any types by correctly introducing WebIDL basic types.

NOTE: If you as a reviewer think this PR is still too big to review in your free time, please tell me and I will split this PR once more. Any feedback will be much appreciated.

[mhegazy]

@saschanaz with #383 in, can you update the change to merge in the .json file

[saschanaz]

to merge in the .json file

Does that mean we want to merge into the existing browser.webidl.preprocessed.json file?

We may just get Web IDL files directly in this repo and use them.

[mhegazy]

Does that mean we want to merge into the existing browser.webidl.preprocessed.json file?

No, i meant like we are doing with the override and added types, just like: https://github.com/Microsoft/TSJS-lib-generator/blob/master/src/index.ts#L91-L94.

My concern is to have a way to know what changed easily to avoid breaking changes. So what i am suggesting is to add the webidl files one at a time, merge the new webidl file with the existing definitions and generate the output, this way we have an easy way to see what changed, then remove the current browser.idl file at the end.

[saschanaz]

That will be great. So, my current plan is put inputfiles/idl/${spec name}.widl, write an WIDL-to-JSON converter module (using webidl2.js package), and then merge them into the existing definitions. Sounds good?

[mhegazy]

sounds great, and sorry again for the delay.

[saschanaz]

See #405 if anyone has subscribed this 😁