"exceptZero" for "signDisplay" option of Intl.NumberFormat() constructor options object

[bolatovumar]

lib Update Request

In TS 4.4.4 signDisplay options of Intl.NumberFormat() constructor options object used to be of type string. See here:

TypeScript/src/lib/es2020.intl.d.ts

Line 267 in f633446

signDisplay?: string;

That was changed in this PR: #45647. Now it's of type "auto" | "never" | "always" | undefined. However, I believe this type union is incomplete and should also include "exceptZero" (see MDN and spec links below). As a result starting from TS 4.5.0-beta (or possibly earlier, I didn't test versions between 4.4.4 and 4.5.0-beta) you now get an error if you try to instantiate Intl.NumberFormat with signDisplay option set to "exceptZero".

Configuration Check

My compilation target is ES2015 and my lib is the default.

Missing / Incorrect Definition

I'm expecting "exceptZero" to be a valid value for signDisplay option of Intl.NumberFormat() constructor options object.

Sample Code

const numberFormatter = new Intl.NumberFormat('en', {
    signDisplay: 'exceptZero' // expect `exceptZero` to be a valid value but it's not according to type definitions
});

Documentation Link

See MDN: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat#parameters
See spec: https://402.ecma-international.org/7.0/#sec-getoption

[iAziz786]

I would like to pick this issue.

[iAziz786]

I assume adding the missing type in the union will do the work?

[bolatovumar]

@iAziz786 yeah, that's correct.

[iAziz786]

Cool, @DanielRosenwasser may I request for the PR to review by anyone?

[ArthurGuez]

Hi there,

I've updated Typescript to 4.5.5 but I'm still having the aforementioned issue. Has the fix been applied?