Merge pull request #2239 from tetsuharuohzeki/bump-min-es2020

Use ES2020 as our ESM format

README.md

@@ -118,7 +118,7 @@ We target to run in following environments.
     - [ECMA262 2017 edition](https://262.ecma-international.org/8.0/).
     - TypeScript's latest version.
 - Module system
-    - ES Module ([ES2015](https://262.ecma-international.org/6.0/) level).
+    - ES Module ([ES2020](https://262.ecma-international.org/11.0/) level).
     - CommonJS
     - A runtime environment or module bundler must support Node.js' [package.json's `exports` field](https://nodejs.org/api/packages.html#package-entry-points) (Newer is better).
 

package.json

@@ -9,6 +9,7 @@
     "devDependencies": {
         "@babel/core": "^7.24.5",
         "@babel/plugin-syntax-typescript": "^7.24.1",
+        "@babel/plugin-transform-export-namespace-from": "^7.24.1",
         "@babel/plugin-transform-modules-commonjs": "^7.24.1",
         "@eslint/js": "^9.2.0",
         "@reflink/reflink": "^0.1.16",

packages/option-t/src/maybe/namespace.ts

@@ -1,5 +1 @@
-// We still use ES2015 as a module format.
-// eslint-disable-next-line @typescript-eslint/naming-convention
-import * as Maybe from './internal/intermediate_namespace.js';
-
-export { Maybe };
+export * as Maybe from './internal/intermediate_namespace.js';

packages/option-t/src/nullable/namespace.ts

@@ -1,5 +1 @@
-// We still use ES2015 as a module format.
-// eslint-disable-next-line @typescript-eslint/naming-convention
-import * as Nullable from './internal/intermediate_namespace.js';
-
-export { Nullable };
+export * as Nullable from './internal/intermediate_namespace.js';

packages/option-t/src/plain_option/namespace.ts

@@ -4,8 +4,4 @@
  *  Consider to use `Nullable<T>`, `Undefinable<T>`, or `Maybe<T>` to express an absence of a value.
  *  In JavaScript, they satisfy almost use cases. Probably, you might not have to use this type.
  */
-// We still use ES2015 as a module format.
-// eslint-disable-next-line @typescript-eslint/naming-convention
-import * as Option from './internal/intermediate_namespace.js';
-
-export { Option };
+export * as Option from './internal/intermediate_namespace.js';

packages/option-t/src/plain_result/namespace.ts

@@ -1,5 +1 @@
-// We still use ES2015 as a module format.
-// eslint-disable-next-line @typescript-eslint/naming-convention
-import * as Result from './internal/intermediate_namespace.js';
-
-export { Result };
+export * as Result from './internal/intermediate_namespace.js';

packages/option-t/src/undefinable/namespace.ts

@@ -1,5 +1 @@
-// We still use ES2015 as a module format.
-// eslint-disable-next-line @typescript-eslint/naming-convention
-import * as Undefinable from './internal/intermediate_namespace.js';
-
-export { Undefinable };
+export * as Undefinable from './internal/intermediate_namespace.js';

packages/option-t/tools/babel/babelrc.cjs.mjs

@@ -20,5 +20,6 @@ export default {
                 strict: true,
             },
         ],
+        ['@babel/plugin-transform-export-namespace-from', {}],
     ],
 };