Type mismatch is xdmp.login -- null is not assignable to undefined

[sjordan1975]

Given the following:
xdmp.login("username", null, true, ["sa-librarian"])

Typescript validator complains:
Argument of type 'null' is not assignable to parameter of type 'string|undefined'

xdmp.login documentation: https://docs.marklogic.com/xdmp.login
xdmp.login("username", null)

[grtjn]

@christyharagan, what would you make of this?

[christyharagan]

Aha, this is new typing in TypeScript 2 onwards. It does a great job of disambiguating null and undefined values.

In this case, the xdmp.login function will have a signature:

(username:string, password?:string)

Where the ? means "optional" and essentially translates to the type: string|undefined.

TypeScript treats null and undefined as different values (as it should), thus the typing error.

As the current typings work, the correct usage this function is either:

xdmp.login("username")

// OR

xdmp.login("username", undefined)

If passing in null to this method is a common pattern, we could alter the typing appropriately. Happy to take suggestions on this.

[grtjn]

The docs (as referenced by OP) talk about null, not undefined, but perhaps both actually works? Using null here makes more sense to me personally too..

[rickypowell]

So if we mark the function parameters as follows, we can accommodate both usages and avoid breaking interfaces.

(username:string, password?:string|null|undefined)

[grtjn]

That last comment was helpful, including this in the mL9 release..