Add `Intl.supportedValuesOf` enumeration to `lib.*.intl.d.ts` as support in Node.js18, and v8, and various browsers exists

[23RoMax]

lib Update Request

Configuration Check

My compilation target is ES2022 and my lib is "esnext.intl", "es2021.intl", "ESNext","ES2022", "ES2021", "es6".

Missing / Incorrect Definition

The static method Intl.supportedValuesOf is supported by Node.js since v18 release from April. This is missing in the definition of Intl.

Sample Code

Intl.supportedValuesOf("timeZone").forEach(function(timeZone) {
   console.log(timeZone);
});

Documentation Link

Ecmascript - it is listed as a stage3 proposal, but given that it is already implemented in v8 & mentioned in the MDN this seems reasonable.

[23RoMax]

As a temporary solution, I extended the existing type declaration

declare namespace Intl {
  type Key = 'calendar' | 'collation' | 'currency' | 'numberingSystem' | 'timeZone' | 'unit';

  function supportedValuesOf(input: Key): string[];
}

[RyanCavanaugh]

Tagging this help wanted but we'd like to wait until this is shipping in Chrome/Edge before getting a PR for it

[IanVoxSmart]

I've just tried it in Chrome 103.0.5060.134 (Linux) and it's supported.

[peetjvv]

Can confirm it also works on Chrome 106.0.5249.91 and Firefox 105.0.1 in Windows 10.

[karlhorky]

Also available in Node.js LTS (18.18.0):

> Intl.supportedValuesOf('timeZone')
[
  'Africa/Abidjan',
  'Africa/Accra',
  'Africa/Addis_Ababa',
  'Africa/Algiers',
  'Africa/Asmera',
  'Africa/Bamako',
  'Africa/Bangui',
  'Africa/Banjul',
  'Africa/Bissau',
  ... 419 more items
]

[chucamphong]

Any update?

[ConcernedHobbit]

https://caniuse.com/mdn-javascript_builtins_intl_supportedvaluesof

The global support percentage is ~90%, and as Node also supports it I don't see what the blocker for this is.

[danielmarcano]

Hi, @sandersn.

This is still throwing an error in a Next.js project v13.0.5 with TypeScript v5.0.4:

Here's my tsconfig.json file:

{
  "compilerOptions": {
    /* Visit https://aka.ms/tsconfig.json to read more about this file */
    /* Language and Environment */
    "target": "es5" /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */,
    "lib": [
      "dom",
      "dom.iterable",
      "esnext"
    ] /* Specify a set of bundled library declaration files that describe the target runtime environment. */,
    "jsx": "preserve" /* Specify what JSX code is generated. */,
    /* Modules */
    "module": "commonjs" /* Specify what module code is generated. */,
    "moduleResolution": "node" /* Specify how TypeScript looks up a file from a given module specifier. */,
    "resolveJsonModule": true /* Enable importing .json files */,
    /* JavaScript Support */
    "allowJs": true /* Allow JavaScript files to be a part of your program. Use the `checkJS` option to get errors from these files. */,
    /* Emit */
    "noEmit": true /* Disable emitting files from a compilation. */,
    /* Interop Constraints */
    "isolatedModules": true /* Ensure that each file can be safely transpiled without relying on other imports. */,
    "esModuleInterop": true /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables `allowSyntheticDefaultImports` for type compatibility. */,
    "forceConsistentCasingInFileNames": true /* Ensure that casing is correct in imports. */,
    /* Type Checking */
    "strict": true /* Enable all strict type-checking options. */,
    "noImplicitAny": true /* Enable error reporting for expressions and declarations with an implied `any` type.. */,
    "strictNullChecks": true /* When type checking, take into account `null` and `undefined`. */,
    "strictFunctionTypes": true /* When assigning functions, check to ensure parameters and the return values are subtype-compatible. */,
    "strictBindCallApply": true /* Check that the arguments for `bind`, `call`, and `apply` methods match the original function. */,
    "strictPropertyInitialization": true /* Check for class properties that are declared but not set in the constructor. */,
    "noImplicitThis": true /* Enable error reporting when `this` is given the type `any`. */,
    "alwaysStrict": true /* Ensure 'use strict' is always emitted. */,
    "noUnusedLocals": true /* Enable error reporting when a local variables aren't read. */,
    "noUnusedParameters": true /* Raise an error when a function parameter isn't read */,
    "noImplicitReturns": true /* Enable error reporting for codepaths that do not explicitly return in a function. */,
    "noFallthroughCasesInSwitch": true /* Enable error reporting for fallthrough cases in switch statements. */,
    "noImplicitOverride": true /* Ensure overriding members in derived classes are marked with an override modifier. */,
    "skipLibCheck": true /* Skip type checking all .d.ts files. */,
    "incremental": true,
    "baseUrl": ".",
    "paths": {
      "$/*": ["./src/*"]
    }
  },
  "include": [
    "custom.d.ts",
    "next-env.d.ts",
    "**/*.ts",
    "**/*.tsx",
    "src/styles/fonts.css",
    "@types/*.d.ts",
  ],
  "exclude": ["node_modules", "jest.setup.js"]
}

[sandersn]

That's right, the change doesn't ship until Typescript 5.1

[maxprilutskiy]

Upgrading typescript to ^5.1.3 solved the problem!

[michealroberts]

On typescript version 5.2.2 and I am seeing this error ... any ideas what I need to do with my tsconfig to get things to work?

[sandersn]

Looks like you need lib to include "es2022". If you have more questions, try asking on the Typescript discord. It's perfect for questions like these.