[lib.webworker.d.ts] Worker constructor type missing optional options

[AviVahl]

TypeScript Version: 3.1.3 (not fixed in master as well)
https://github.com/Microsoft/TypeScript/blob/release-3.1/lib/lib.webworker.d.ts#L2699

Search Terms:
web worker options

Code

new Worker('https://some-url', {type: 'module'})

Expected behavior:
Type check should pass.

Actual behavior:
Second (options) parameter isn't specified in Worker types, so type check fails.

Playground Link:
http://www.typescriptlang.org/play/#src=new%20Worker('https%3A%2F%2Fsome-url'%2C%20%7Btype%3A%20'module'%7D)

Related Issues:
Couldn't find existing issue discussing this.

Reference:
https://developer.mozilla.org/en-US/docs/Web/API/Worker/Worker

[weswigham]

PRs welcomed. You can find more information about contributing lib.d.ts fixes at https://github.com/Microsoft/TypeScript/blob/master/CONTRIBUTING.md#contributing-libdts-fixes.

[AviVahl]

@weswigham I gave it a try... cloned the tsjs-lib-generator repo, edited overridingTypes.json > interfaces >interface > Worker, adding:

"constructor": {
    "override-signatures": [
        "new(stringUrl: string, options?: WorkerOptions): Worker"
    ]
},

That seemed to modify the generated constructor the way I wanted.

I couldn't, however, find a proper way to add the WorkerOptions interface. Tried adding it to addedTypes.json > mixins:

"WorkerOptions": {
    "name": "WorkerOptions",
    "properties": {
        "property": {
            "type": {
                "name": "type",
                "override-type": "WorkerType",
                "required": 0
            },
            "credentials": {
                "name": "credentials",
                "override-type": "RequestCredentials",
                "required": 0
            },
            "name": {
                "name": "name",
                "override-type": "string",
                "required": 0
            }
        }
    }
}

but that resulted in a global WorkerOptions constructor variable.

Not sure I'm even editing the correct files. Could use any pointers... :)

[weswigham]

I think we normally use the dictionaries section for interfaces.

[AviVahl]

@weswigham thx for the tip. I also had to adjust knownTypes.json for the interface to actually be exposed. Opened PR.