[WIP] V4

.github/workflows/ci.yml

@@ -46,7 +46,7 @@ jobs:
       - run: npm ci
       - run: npx run-s bundle test-unit-bun
 
-  promises-and-observables:
+  promises:
     strategy:
       matrix:
         node:
@@ -64,7 +64,7 @@ jobs:
           node-version: ${{ matrix.node }}
           cache: npm
       - run: npm ci
-      - run: npx run-s test-promises test-observables
+      - run: npm run test-promises
 
   tests:
     strategy:
@@ -88,4 +88,4 @@ jobs:
           node-version: ${{ matrix.node }}
           cache: npm
       - run: npm ci
-      - run: npx run-s bundle test-unit-node test-entries test-compat-data test-compat-tools test-builder
+      - run: npx run-s bundle test-unit-node test-entries test-compat-data test-compat-tools test-builder test-babel-plugin

.gitignore

@@ -13,37 +13,39 @@ node_modules/
 /docs/web/changelog.md
 /docs/web/contributing.md
 /docs/web/security.md
-/packages/core-js/features/
-/packages/core-js/es/index.js
-/packages/core-js/full/index.js
-/packages/core-js/stable/index.js
+/packages/core-js/actual/
+/packages/core-js/es/
+/packages/core-js/full/
+/packages/core-js/proposals/
+/packages/core-js/stable/
+/packages/core-js/stage/
+/packages/core-js/index.js
 /packages/core-js/LICENSE
+/packages/core-js-babel-plugin/LICENSE
 /packages/core-js-builder/LICENSE
 /packages/core-js-bundle/LICENSE
 /packages/core-js-bundle/index.js
 /packages/core-js-bundle/minified.js
 /packages/core-js-bundle/minified.js.map
-/packages/core-js-bundle/postinstall.js
 /packages/core-js-compat/LICENSE
+/packages/core-js-compat/built-in-definitions.json
 /packages/core-js-compat/data.json
 /packages/core-js-compat/entries.json
+/packages/core-js-compat/entries-by-versions.json
 /packages/core-js-compat/external.json
 /packages/core-js-compat/modules.json
 /packages/core-js-compat/modules-by-versions.json
 /packages/core-js-pure/actual/
 /packages/core-js-pure/es/
-/packages/core-js-pure/features/
 /packages/core-js-pure/full/
 /packages/core-js-pure/internals/
 /packages/core-js-pure/modules/
 /packages/core-js-pure/proposals/
 /packages/core-js-pure/stable/
 /packages/core-js-pure/stage/
-/packages/core-js-pure/web/
 /packages/core-js-pure/LICENSE
 /packages/core-js-pure/index.js
 /packages/core-js-pure/configurator.js
-/packages/core-js-pure/postinstall.js
 /tests/**/bundles/
 /tests/compat/*.jar
 /tests/compat/compat-data.js

CONTRIBUTING.md

@@ -12,21 +12,21 @@ There is always some ["help wanted" issues](https://github.com/zloirock/core-js/
 - The polyfill should properly work in ES3 and all possible engines. If in some engines it cannot be implemented (for example, it strictly requires more modern ES or unavailable platform features), it should not break any other `core-js` features or application in any way.
 - Avoid possible observing / breakage polyfills via patching built-ins at runtime: cache all global built-ins in the polyfills code and don't call prototype methods from instances.
 - Shared helpers should be added to the [`packages/core-js/internals`](./packages/core-js/internals) directory. Reuse already existing helpers.
-- Avoid direct import from `/modules/` path in `/internals|modules/` since it will break optimizations via Babel / `swc`. Specify such dependencies in `/es|stable|actual/full/` entries and use something like [`internals/get-built-in`](./packages/core-js/internals/get-built-in.js) helpers.
+- Avoid direct import from `/modules/` path in `/internals|modules/` since it will break optimizations via Babel / `swc`. Specify such dependencies with comments like `// dependency: es.string.iterator` directly in your module, they will be automatically added to entries, and use something like [`internals/get-built-in`](./packages/core-js/internals/get-built-in.js) helpers.
 - For export the polyfill, in all common cases use [`internals/export`](./packages/core-js/modules/export.js) helper. Use something else only if this helper is not applicable - for example, if you want to polyfill accessors.
-- If the code of the pure version implementation should significantly differ from the global version (*that's not a frequent situation, in most cases [`internals/is-pure`](./packages/core-js/modules/is-pure.js) constant is enough*), you can add it to [`packages/core-js-pure/override`](./packages/core-js-pure/override) directory. The rest parts of `core-js-pure` will be copied from `core-js` package.
-- Add the feature detection of the polyfill to [`tests/compat/tests.js`](./tests/compat/tests.js), add the compatibility data to [`packages/core-js-compat/src/data.mjs`](./packages/core-js-compat/src/data.mjs), how to do it [see below](#how-to-update-core-js-compat-data), and the name of the polyfill module to [`packages/core-js-compat/src/modules-by-versions.mjs`](./packages/core-js-compat/src/modules-by-versions.mjs) (this data is also used for getting the default list of polyfills at bundling and generation indexes).
-- Add it to entry points where it's required: directories [`packages/core-js/es`](./packages/core-js/es), [`packages/core-js/stable`](./packages/core-js/stable), [`packages/core-js/actual`](./packages/core-js/actual), [`packages/core-js/full`](./packages/core-js/full), [`packages/core-js/proposals`](./packages/core-js/proposals), [`packages/core-js/stage`](./packages/core-js/stage) and [`packages/core-js/web`](./packages/core-js/web).
+- If the code of the pure version implementation should significantly differ from the global version (*that's not a frequent situation, in most cases [`internals/is-pure`](./packages/core-js/modules/is-pure.js) constant is enough*), you can add it to [`packages/core-js-pure/override`](./packages/core-js-pure/override) directory. The rest parts of `@core-js/pure` will be copied from `core-js` package.
+- Add the feature detection of the polyfill to [`tests/compat/tests.js`](./tests/compat/tests.js), add the compatibility data to [`packages/core-js-compat/src/data.mjs`](./packages/core-js-compat/src/data.mjs), how to do it [see below](#how-to-update-core-js-compat-data).
+- Add it to entries definitions, see [`scripts/build-entries/entries-definitions.mjs`](./scripts/build-entries/entries-definitions.mjs).
 - Add unit tests to [`tests/unit-global`](./tests/unit-global) and [`tests/unit-pure`](./tests/unit-pure).
 - Add tests of entry points to [`tests/entries/unit.mjs`](./tests/entries/unit.mjs).
 - Make sure that you are following [our coding style](#style-and-standards) and [all tests](#testing) are passed.
 - Document it in [site documentation](./docs/web/docs/) and [CHANGELOG.md](./CHANGELOG.md).
 
 [A simple example of adding a new polyfill.](https://github.com/zloirock/core-js/pull/1294/files)
 
-## How to update `core-js-compat` data
+## How to update `@core-js/compat` data
 
-For updating `core-js-compat` data:
+For updating `@core-js/compat` data:
 
 - If you want to add a new data for a browser, run in this browser `tests/compat/index.html` (tests and results for the actual release are available at [`http://zloirock.github.io/core-js/compat/`](http://zloirock.github.io/core-js/compat/)) and you will see what `core-js` modules are required for this browser.
 
@@ -57,7 +57,6 @@ engine            | how to run tests | base data inherits from    | mandatory ch
 `node`            | node runner      | `chrome` (only ES)         | non-ES features  | required
 `opera`           | browser runner   | `chrome`                   |                  | if inconsistent (!= `chrome` - 16)
 `opera-android`   | browser runner   | `opera`, `chrome-android`  |                  | required
-`phantom`         | browser runner   | `safari`                   |                  |
 `quest`           | browser runner   | `chrome-android`           |                  | required
 `react-native`    | hermes runner    | `hermes`                   | required         |
 `rhino`           | rhino runner     |                            | required         |
@@ -71,9 +70,9 @@ If you have no access to all required browsers / versions of browsers, use [Sauc
 The coding style should follow our [`eslint.config.js`](./tests/eslint/eslint.config.js). You can test it by calling [`npm run lint`](#testing). Different places have different syntax and standard library limitations:
 - Polyfill implementations should use only ES3 syntax and standard library, they should not use other polyfills from the global scope.
 - Unit tests should use the modern syntax with our [minimalistic Babel config](./babel.config.js). Unit tests for the pure version should not use any modern standard library features.
-- Tools, scripts and tests, performed in NodeJS, should use only the syntax and the standard library available in NodeJS 8.
+- Tools, scripts and tests, performed in NodeJS, should use only the syntax and the standard library available in NodeJS 20.
 
-File names should be in the kebab-case. Name of polyfill modules should follow the naming convention `namespace.subnamespace-where-required.feature-name`, for example, `esnext.set.intersection`. The top-level namespace should be `es` for stable ECMAScript features, `esnext` for ECMAScript proposals and `web` for other web standards.
+File names should be in the kebab-case. Name of polyfill modules should follow the naming convention `namespace.subnamespace-where-required.feature-name`, for example, `es.set.intersection`. The top-level namespace should be `es` for stable ECMAScript features, `esnext` for ECMAScript proposals and `web` for other web standards.
 
 ## Testing
 
@@ -110,19 +109,15 @@ You can run parts of the test case separately:
   ```sh
   npx run-s prepare test-promises
   ```
-- [ECMAScript `Observable` test case](https://github.com/tc39/proposal-observable):
-  ```sh
-  npx run-s prepare test-observables
-  ```
 - CommonJS entry points tests:
   ```sh
   npx run-s prepare test-entries
   ```
-- `core-js-compat` tools tests:
+- `@core-js/compat` tools tests:
   ```sh
   npx run-s prepare test-compat-tools
   ```
-- `core-js-builder` tests:
+- `@core-js/builder` tests:
   ```sh
   npx run-s prepare test-builder
   ```

LICENSE

@@ -1,19 +1,31 @@
-Copyright (c) 2014-2025 Denis Pushkarev, 2025 CoreJS Company
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
+## core-js experimental version license
+
+### Copyright (c) 2014-2025 Denis Pushkarev, 2025 CoreJS Company
+
+### Non-Commercial Use Only
+* The Software may be used strictly for non-commercial purposes. Any commercial use — including but not limited to selling, sublicensing, using in commercial services, or including in commercial products — is expressly prohibited.
+
+### Experimental Use Only
+* The Software is provided solely for experimental, research, and evaluation purposes. The user acknowledges that the Software is in a pre-release or developmental stage and may be unstable, contain bugs, or be incomplete.
+
+### Term of the License
+* This license is valid only until an official stable version 4 of core-js is released.
+* Within 7 calendar days of such release, the user must either:
+  - Transition to the stable version under its applicable license, or
+  - Cease all use of this experimental version.
+* Continued use beyond this period is strictly prohibited.
+
+### Disclaimer of Warranty
+* The Software is provided "as is", without warranty of any kind, express or implied, including but not limited to warranties of merchantability, fitness for a particular purpose, or non-infringement.
+
+### Limited Redistribution
+* Redistribution of the Software as part of a non-commercial website or web-based project is permitted, provided that:
+  - The Software is not modified, and
+  - It is used solely in accordance with the terms of this license.
+* Any other form of redistribution, sublicense, or share is prohibited without prior written permission from the copyright holder.
+
+### Prohibition on Use for AI Training
+* The Software, including its source code and any derived works, may not be used, in whole or in part, for the training or fine-tuning of machine learning models or artificial intelligence systems, whether commercial or non-commercial, without explicit prior written permission from the copyright holder.
+
+### Governing Law
+* This license shall be governed by and construed in accordance with the laws of the State of Delaware, United States of America, without regard to its conflict of law principles.