Incorrect type for exact matches in ChoiceOptions of plural macro

[tstehr]

Description

The exact match type in ChoicesOption is defined as: [digit: `${number}`]: string, which implies it should be used as follows:

const message = plural(count, {
  '0': "No Books",
  one: "# Book",
  other: "# Books",
});

However, the correct key in MessageFormat syntax is be "=0" not just "0":

const message = plural(count, {
  '=0': "No Books",
  one: "# Book",
  other: "# Books",
});

This works as expected, but leads to a type error. To fix that, the index signature in ChoicesOption should be [digit: `=${number}`]: string.

Verifications

• I've checked the docs and this isn't covered there.
• I've searched existing issues on GitHub.

Reproduction Steps

The following code, which works correctly, creates a type error:

const message = plural(count, {
  '=0': "No Books",
  one: "# Book",
  other: "# Books",
});

Expected Behavior

There should not be a type error.

Macro Support

SWC with @lingui/swc-plugin

Lingui Version

5.3.3

Babel Version

Framework

Vite

[timofei-iatsenko]

The typing is correct, it's automatically adds = for exact matches

import { plural } from "@lingui/core/macro";
plural(users.length, {
  offset: 1,
  0: "No books",
  1: "1 book",
  other: someOtherExp,
});

/// ↓ ↓ ↓ ↓ ↓ ↓

import { i18n as _i18n } from "@lingui/core";
_i18n._(
  /*i18n*/
  {
    id: "0mcXIe",
    message:
      "{0, plural, offset:1 =0 {No books} =1 {1 book} other {{someOtherExp}}}",
    values: {
      0: users.length,
      someOtherExp: someOtherExp,
    },
  },
);