build: Add Elastic v2 licence (#14)

Author: sddonne

LICENCE.txt

@@ -0,0 +1,93 @@
+Elastic License 2.0
+
+URL: https://www.elastic.co/licensing/elastic-license
+
+## Acceptance
+
+By using the software, you agree to all of the terms and conditions below.
+
+## Copyright License
+
+The licensor grants you a non-exclusive, royalty-free, worldwide,
+non-sublicensable, non-transferable license to use, copy, distribute, make
+available, and prepare derivative works of the software, in each case subject to
+the limitations and conditions below.
+
+## Limitations
+
+You may not provide the software to third parties as a hosted or managed
+service, where the service provides users with access to any substantial set of
+the features or functionality of the software.
+
+You may not move, change, disable, or circumvent the license key functionality
+in the software, and you may not remove or obscure any functionality in the
+software that is protected by the license key.
+
+You may not alter, remove, or obscure any licensing, copyright, or other notices
+of the licensor in the software. Any use of the licensor’s trademarks is subject
+to applicable law.
+
+## Patents
+
+The licensor grants you a license, under any patent claims the licensor can
+license, or becomes able to license, to make, have made, use, sell, offer for
+sale, import and have imported the software, in each case subject to the
+limitations and conditions in this license. This license does not cover any
+patent claims that you cause to be infringed by modifications or additions to
+the software. If you or your company make any written claim that the software
+infringes or contributes to infringement of any patent, your patent license for
+the software granted under these terms ends immediately. If your company makes
+such a claim, your patent license ends immediately for work on behalf of your
+company.
+
+## Notices
+
+You must ensure that anyone who gets a copy of any part of the software from you
+also gets a copy of these terms.
+
+If you modify the software, you must include in any modified copies of the
+software prominent notices stating that you have modified the software.
+
+## No Other Rights
+
+These terms do not imply any licenses other than those expressly granted in
+these terms.
+
+## Termination
+
+If you use the software in violation of these terms, such use is not licensed,
+and your licenses will automatically terminate. If the licensor provides you
+with a notice of your violation, and you cease all violation of this license no
+later than 30 days after you receive that notice, your licenses will be
+reinstated retroactively. However, if you violate these terms after such
+reinstatement, any additional violation of these terms will cause your licenses
+to terminate automatically and permanently.
+
+## No Liability
+
+*As far as the law allows, the software comes as is, without any warranty or
+condition, and the licensor will not be liable to you for any damages arising
+out of these terms or the use or nature of the software, under any kind of
+legal claim.*
+
+## Definitions
+
+The **licensor** is the entity offering these terms, and the **software** is the
+software the licensor makes available under these terms, including any portion
+of it.
+
+**you** refers to the individual or entity agreeing to these terms.
+
+**your company** is any legal entity, sole proprietorship, or other kind of
+organization that you work for, plus all organizations that have control over,
+are under the control of, or are under common control with that
+organization. **control** means ownership of substantially all the assets of an
+entity, or the power to direct its management and policies by vote, contract, or
+otherwise. Control can be direct or indirect.
+
+**your licenses** are all the licenses granted to you for the software under
+these terms.
+
+**use** means anything you do with the software requiring one of your licenses.
+
+**trademark** means trademarks, service marks, and similar rights.

NOTICE.txt

@@ -0,0 +1,2 @@
+esql-js (A set of ts tools to parse, build and transform ES|QL queries programatically).
+Copyright 2026 Elasticsearch B.V.

README.md

@@ -165,4 +165,4 @@ console.log(text);
 ```
 
 ## Licence
-TBD
+Licensed under [Elastic License 2.0](./LICENCE.txt).

eslint.config.js

@@ -1,15 +1,24 @@
-// ESLint flat config for TypeScript.
 import { defineConfig, globalIgnores } from 'eslint/config';
 import eslint from '@eslint/js';
 import tseslint from 'typescript-eslint';
 import eslintConfigPrettier from 'eslint-config-prettier';
+import { requireLicenseHeader } from './lint-licence-rule.js';
 
 export default defineConfig([
-  globalIgnores(['lib/', 'node_modules/', 'src/parser/antlr/']),
+  globalIgnores(['lib/', 'node_modules/', 'src/parser/antlr/', '*.js', '*.mjs']),
   eslint.configs.recommended,
   ...tseslint.configs.recommended,
   {
+    plugins: {
+      'local-rules': {
+        rules: {
+          'require-license-header': requireLicenseHeader,
+        },
+      },
+    },
     rules: {
+      'local-rules/require-license-header': 'error',
+
       // TypeScript handles this natively; ESLint's no-undef doesn't understand TS types
       'no-undef': 'off',
 

lint-licence-rule.js

@@ -0,0 +1,129 @@
+import babelEslint from '@babel/eslint-parser';
+
+const licenseHeader = `/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */`;
+
+export const requireLicenseHeader = {
+  meta: {
+    fixable: 'code',
+    schema: [
+      {
+        type: 'object',
+        properties: {
+          license: {
+            type: 'string',
+          },
+        },
+        additionalProperties: false,
+      },
+    ],
+  },
+  create: (context) => {
+    return {
+      Program(program) {
+        const license = init(context, program, function () {
+          const parsed = babelEslint.parse(licenseHeader, { requireConfigFile: false });
+          assert(!parsed.body.length, '"license" option must only include a single comment');
+          assert(
+            parsed.comments.length === 1,
+            '"license" option must only include a single comment'
+          );
+
+          return {
+            source: licenseHeader,
+            nodeValue: normalizeWhitespace(parsed.comments[0].value),
+          };
+        });
+
+        if (!license) {
+          return;
+        }
+
+        const sourceCode = context.sourceCode;
+        const comment = sourceCode
+          .getAllComments()
+          .find((node) => normalizeWhitespace(node.value) === license.nodeValue);
+
+        // no license comment
+        if (!comment) {
+          context.report({
+            message: 'File must start with a license header',
+            loc: {
+              start: { line: 1, column: 0 },
+              end: { line: 1, column: sourceCode.lines[0].length - 1 },
+            },
+            fix(fixer) {
+              if (isHashbang(sourceCode.lines[0])) {
+                return undefined;
+              }
+
+              return fixer.replaceTextRange([0, 0], licenseHeader + '\n\n');
+            },
+          });
+          return;
+        }
+
+        // ensure there is nothing before the comment
+        const sourceBeforeNode = sourceCode
+          .getText()
+          .slice(0, sourceCode.getIndexFromLoc(comment.loc.start));
+        if (sourceBeforeNode.length && !isHashbang(sourceBeforeNode)) {
+          context.report({
+            node: comment,
+            message: 'License header must be at the very beginning of the file',
+            fix(fixer) {
+              // replace leading whitespace if possible
+              if (sourceBeforeNode.trim() === '') {
+                return fixer.replaceTextRange([0, sourceBeforeNode.length], '');
+              }
+
+              // inject content at top and remove node from current location
+              // if removing whitespace is not possible
+              return [
+                fixer.remove(comment),
+                fixer.replaceTextRange([0, 0], license.source + '\n\n'),
+              ];
+            },
+          });
+        }
+      },
+    };
+  },
+};
+
+function isHashbang(text) {
+  return text.trim().startsWith('#!') && !text.trim().includes('\n');
+}
+
+function assert(truth, message) {
+  if (truth) {
+    return;
+  }
+
+  const error = new Error(message);
+  error.failedAssertion = true;
+  throw error;
+}
+
+function normalizeWhitespace(string) {
+  return string.replace(/\s+/g, ' ');
+}
+
+function init(context, program, initStep) {
+  try {
+    return initStep();
+  } catch (error) {
+    if (error.failedAssertion) {
+      context.report({
+        node: program,
+        message: error.message,
+      });
+    } else {
+      throw error;
+    }
+  }
+}

package.json

@@ -14,6 +14,8 @@
     }
   },
   "files": [
+    "NOTICE.txt",
+    "LICENSE.txt",
     "lib"
   ],
   "scripts": {
@@ -38,9 +40,10 @@
   },
   "repository": "https://github.com/elastic/esql-js.git",
   "private": true,
-  "license": "To be defined",
+  "license": "SEE LICENSE IN LICENSE.txt",
   "sideEffects": false,
   "devDependencies": {
+    "@babel/eslint-parser": "7.28.6",
     "@eslint/js": "10.0.1",
     "@semantic-release/changelog": "6.0.3",
     "@semantic-release/commit-analyzer": "13.0.1",

src/__tests__/fixtures.ts

@@ -1,10 +1,8 @@
 /*
  * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the "Elastic License
- * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
- * Public License v 1"; you may not use this file except in compliance with, at
- * your election, the "Elastic License 2.0", the "GNU Affero General Public
- * License v3.0 only", or the "Server Side Public License, v 1".
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
  */
 
 export const smallest = `FROM a`;

src/ast/builder/builder.test.ts

@@ -1,10 +1,8 @@
 /*
  * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the "Elastic License
- * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
- * Public License v 1"; you may not use this file except in compliance with, at
- * your election, the "Elastic License 2.0", the "GNU Affero General Public
- * License v3.0 only", or the "Server Side Public License, v 1".
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
  */
 
 import { Builder } from '.';

src/ast/builder/builder.ts

@@ -1,10 +1,8 @@
 /*
  * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the "Elastic License
- * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
- * Public License v 1"; you may not use this file except in compliance with, at
- * your election, the "Elastic License 2.0", the "GNU Affero General Public
- * License v3.0 only", or the "Server Side Public License, v 1".
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
  */
 
 /* eslint-disable @typescript-eslint/no-namespace */

src/ast/builder/index.ts

@@ -1,10 +1,8 @@
 /*
  * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the "Elastic License
- * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
- * Public License v 1"; you may not use this file except in compliance with, at
- * your election, the "Elastic License 2.0", the "GNU Affero General Public
- * License v3.0 only", or the "Server Side Public License, v 1".
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
  */
 
 export type * from './types';