microsoft · aeschli · Mar 4, 2026 · Mar 4, 2026 · Mar 4, 2026
diff --git a/.vscode/launch.json b/.vscode/launch.json
@@ -16,11 +16,11 @@
 			"request": "launch",
 			"runtimeArgs": [
 				"--test",
-				"./lib/umd/test/**/*.test.js"
+				"./lib/esm/test/**/*.test.js"
 			],
 			"cwd": "${workspaceRoot}",
 			"sourceMaps": true,
-			"outFiles": [ "${workspaceRoot}/lib/umd/**/*.js" ],
+			"outFiles": [ "${workspaceRoot}/lib/esm/**/*.js" ],
 			"preLaunchTask": "npm: watch"
 		},
 		{

diff --git a/build/bundle-schemas.cjs → build/bundle-schemas.js b/build/bundle-schemas.cjs → build/bundle-schemas.js
@@ -3,23 +3,23 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-const fs = require('fs').promises;
-const Bundler = require("@hyperjump/json-schema-bundle");
+import { writeFile } from 'node:fs/promises';
+import Bundler from '@hyperjump/json-schema-bundle';
 
 (async function () {
-	bundle(`https://json-schema.org/draft/2019-09/schema`, 'draft-2019-09', 'https://json-schema.org/draft/2019-09');
-	bundle(`https://json-schema.org/draft/2020-12/schema`, 'draft-2020-12', 'https://json-schema.org/draft/2020-12');
+	bundle('https://json-schema.org/draft/2019-09/schema', 'draft-2019-09', 'https://json-schema.org/draft/2019-09');
+	bundle('https://json-schema.org/draft/2020-12/schema', 'draft-2020-12', 'https://json-schema.org/draft/2020-12');
 }());
 
 async function bundle(uri, filename, derivedURL) {
 	const metaSchema = await Bundler.get(uri);
 	let bundle = await Bundler.bundle(metaSchema);
 	bundle = JSON.parse(JSON.stringify(bundle, null, 2).replace(/"undefined": ""/g, '"$dynamicAnchor": "meta"'));
-	fs.writeFile(`./${filename}.json`, JSON.stringify(bundle, null, 2), 'utf8');
+	await writeFile(`./${filename}.json`, JSON.stringify(bundle, null, 2), 'utf8');
 	bundle = flattenDraftMetaSchema(bundle);
 	const jsified = getCopyright(derivedURL) + 'export default ' + printObject(bundle);
-	fs.writeFile(`./${filename}-flat.json`, JSON.stringify(bundle, null, 2), 'utf8');
-	fs.writeFile(`./src/services/schemas/${filename}-flat.ts`, jsified, 'utf8');
+	await writeFile(`./${filename}-flat.json`, JSON.stringify(bundle, null, 2), 'utf8');
+	await writeFile(`./src/services/schemas/${filename}-flat.ts`, jsified, 'utf8');
 }
 function getCopyright(derivedURL) {
 	return [
@@ -55,7 +55,7 @@ function indent(level) {
 function printObject(obj, indentLevel = 0) {
 	const result = [];
 	if (Array.isArray(obj)) {
-		result.push(`[`);
+		result.push('[');
 		for (const item of obj) {
 			if (typeof item === 'object' && item !== null) {
 				result.push(`${indent(indentLevel + 1)}${printObject(item, indentLevel + 1)},`);
@@ -67,11 +67,11 @@ function printObject(obj, indentLevel = 0) {
 		return result.join('\n');
 	}
 	if (obj === null) {
-		result.push(`null`);
+		result.push('null');
 		return result.join('\n');
 	}
 
-	result.push(`{`);
+	result.push('{');
 	for (const [key, value] of Object.entries(obj)) {
 		if (typeof value === 'object' && value !== null) {
 			result.push(`${indent(indentLevel + 1)}${printKey(key)}: ${printObject(value, indentLevel + 1)},`);
@@ -106,9 +106,9 @@ function replaceDynamicRefs(node, anchorName = DEFAULT_ANCHOR) {
 	visit(node, (n, k) => {
 		const v = n[k];
 		if (k === '$dynamicRef' && v === '#' + anchorName) {
-			n['$ref'] = '#';
-			delete n['$dynamicRef'];
-		};
+			n.$ref = '#';
+			delete n.$dynamicRef;
+		}
 	});
 }
 
@@ -117,9 +117,9 @@ function replaceRecursiveRefs(node, anchorName = DEFAULT_ANCHOR) {
 	visit(node, (n, k) => {
 		const v = n[k];
 		if (k === '$recursiveRef') {
-			n['$ref'] = v;
-			delete n['$recursiveRef'];
-		};
+			n.$ref = v;
+			delete n.$recursiveRef;
+		}
 	});
 }
 
@@ -130,7 +130,7 @@ function replaceOldRefs(node, anchorName = DEFAULT_ANCHOR) {
 		if (k === '$ref' && typeof v === 'string' && v.startsWith(anchorName + '/')) {
 			const segments = v.split('#');
 			if (segments.length === 2) {
-				n['$ref'] = `#${segments[1]}`;
+				n.$ref = `#${segments[1]}`;
 			}
 		}
 	});
@@ -149,7 +149,7 @@ function stripDynamicAnchors(node) {
 function collectVocabularies(schema) {
 	const vocabularies = [];
 	const defs = schema.$defs || {};
-	for (const [key, value] of Object.entries(defs)) {
+	for (const [, value] of Object.entries(defs)) {
 		if (value && typeof value === 'object' && !Array.isArray(value) && value.$id && value.$dynamicAnchor === DEFAULT_ANCHOR && value.properties) {
 			vocabularies.push(value);
 		}
@@ -251,4 +251,4 @@ function flattenDraftMetaSchema(original) {
 	}
 
 	return schema;
-}
+}
diff --git a/build/remove-sourcemap-refs.js b/build/remove-sourcemap-refs.js
@@ -3,30 +3,33 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-const fs = require('fs');
-const path = require('path');
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
 
 function deleteRefs(dir) {
     const files = fs.readdirSync(dir);
-    for (let file of files) {
+    for (const file of files) {
         const filePath = path.join(dir, file);
         const stat = fs.statSync(filePath);
         if (stat.isDirectory()) {
             deleteRefs(filePath);
         } else if (path.extname(file) === '.js') {
             const content = fs.readFileSync(filePath, 'utf8');
-            const newContent = content.replace(/\/\/\# sourceMappingURL=[^]+.js.map/, '')
+            const newContent = content.replace(/\/\/\# sourceMappingURL=[^]+.js.map/, '');
             if (content.length !== newContent.length) {
                 console.log('remove sourceMappingURL in ' + filePath);
                 fs.writeFileSync(filePath, newContent);
             }
         } else if (path.extname(file) === '.map') {
-            fs.unlinkSync(filePath)
+            fs.unlinkSync(filePath);
             console.log('remove ' + filePath);
         }
     }
 }
 
-let location = path.join(__dirname, '..', 'lib');
+const location = path.join(__dirname, '..', 'lib');
 console.log('process ' + location);
 deleteRefs(location);
diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -1,10 +1,15 @@
 {
   "name": "vscode-json-languageservice",
-  "version": "5.7.2",
+  "version": "6.0.0-next.1",
   "description": "Language service for JSON",
-  "main": "./lib/umd/jsonLanguageService.js",
-  "typings": "./lib/umd/jsonLanguageService",
-  "module": "./lib/esm/jsonLanguageService.js",
+  "type": "module",
+  "types": "./lib/esm/jsonLanguageService.d.ts",
+  "exports": {
+    ".": {
+      "types": "./lib/esm/jsonLanguageService.d.ts",
+      "import": "./lib/esm/jsonLanguageService.js"
+    }
+  },
   "author": "Microsoft Corporation",
   "repository": {
     "type": "git",
@@ -31,18 +36,18 @@
     "@vscode/l10n": "^0.0.18"
   },
   "scripts": {
-    "prepack": "npm run clean && npm run compile-esm && npm run test && npm run remove-sourcemap-refs",
+    "prepack": "npm run clean && npm run compile && npm run test && npm run remove-sourcemap-refs",
     "compile": "tsc -p ./src",
-    "compile-esm": "tsc -p ./src/tsconfig.esm.json",
     "clean": "rimraf lib",
+    "bundle-schemas": "node ./build/bundle-schemas.js",
     "remove-sourcemap-refs": "node ./build/remove-sourcemap-refs.js",
     "watch": "tsc -w -p ./src",
     "pretest": "npm run compile",
-    "test": "node --test ./lib/umd/test/**/*.test.js",
+    "test": "node --test ./lib/esm/test/**/*.test.js",
     "posttest": "npm run lint",
     "coverage": "npx nyc -r lcov npm run test",
     "lint": "eslint src/**/*.ts",
     "install-types-next": "npm install vscode-languageserver-types@next -f -S && npm install vscode-languageserver-textdocument@next -f -S",
-    "sample": "npm run compile && node ./lib/umd/example/sample.js"
+    "sample": "npm run compile && node ./lib/esm/example/sample.js"
   }
 }
diff --git a/src/example/sample.ts b/src/example/sample.ts
@@ -1,6 +1,6 @@
 
 
-import { getLanguageService, TextDocument } from '../jsonLanguageService';
+import { getLanguageService, TextDocument } from '../jsonLanguageService.js';
 
 async function main() {
     const jsonContentUri = 'foo://server/example.data.json';

diff --git a/src/jsonContributions.ts b/src/jsonContributions.ts
@@ -2,7 +2,7 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
-import { MarkedString, CompletionItem } from './jsonLanguageService';
+import { MarkedString, CompletionItem } from './jsonLanguageService.js';
 
 export interface JSONWorkerContribution {
 	getInfoContribution(uri: string, location: JSONPath): PromiseLike<MarkedString[]>;

diff --git a/src/jsonLanguageService.ts b/src/jsonLanguageService.ts
@@ -3,18 +3,18 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { JSONCompletion } from './services/jsonCompletion';
-import { JSONHover } from './services/jsonHover';
-import { JSONValidation } from './services/jsonValidation';
+import { JSONCompletion } from './services/jsonCompletion.js';
+import { JSONHover } from './services/jsonHover.js';
+import { JSONValidation } from './services/jsonValidation.js';
 
-import { JSONDocumentSymbols } from './services/jsonDocumentSymbols';
-import { parse as parseJSON, newJSONDocument } from './parser/jsonParser';
-import { schemaContributions } from './services/configuration';
-import { JSONSchemaService } from './services/jsonSchemaService';
-import { getFoldingRanges } from './services/jsonFolding';
-import { getSelectionRanges } from './services/jsonSelectionRanges';
-import { sort } from './utils/sort';
-import { format } from './utils/format';
+import { JSONDocumentSymbols } from './services/jsonDocumentSymbols.js';
+import { parse as parseJSON, newJSONDocument } from './parser/jsonParser.js';
+import { schemaContributions } from './services/configuration.js';
+import { JSONSchemaService } from './services/jsonSchemaService.js';
+import { getFoldingRanges } from './services/jsonFolding.js';
+import { getSelectionRanges } from './services/jsonSelectionRanges.js';
+import { sort } from './utils/sort.js';
+import { format } from './utils/format.js';
 
 import {
 	ASTNode,
@@ -24,15 +24,15 @@ import {
 	TextDocument,
 	Position, CompletionItem, CompletionList, Hover, Range, SymbolInformation, Diagnostic,
 	TextEdit, FormattingOptions, DocumentSymbol, DefinitionLink, MatchingSchema, JSONLanguageStatus, SortOptions
-} from './jsonLanguageTypes';
-import { findLinks } from './services/jsonLinks';
+} from './jsonLanguageTypes.js';
+import { findLinks } from './services/jsonLinks.js';
 import { DocumentLink } from 'vscode-languageserver-types';
 
 export type JSONDocument = {
 	root: ASTNode | undefined;
 	getNodeFromOffset(offset: number, includeRightBound?: boolean): ASTNode | undefined;
 };
-export * from './jsonLanguageTypes';
+export * from './jsonLanguageTypes.js';
 
 export interface LanguageService {
 	configure(settings: LanguageSettings): void;

diff --git a/src/jsonLanguageTypes.ts b/src/jsonLanguageTypes.ts
@@ -3,8 +3,8 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { JSONWorkerContribution, JSONPath, Segment, CompletionsCollector } from './jsonContributions';
-import { JSONSchema } from './jsonSchema';
+import { JSONWorkerContribution, JSONPath, Segment, CompletionsCollector } from './jsonContributions.js';
+import { JSONSchema } from './jsonSchema.js';
 import {
 	Range, Position, DocumentUri, MarkupContent, MarkupKind,
 	Color, ColorInformation, ColorPresentation,

diff --git a/src/parser/jsonParser.ts b/src/parser/jsonParser.ts
@@ -4,10 +4,10 @@
  *--------------------------------------------------------------------------------------------*/
 
 import * as Json from 'jsonc-parser';
-import { JSONSchema, JSONSchemaRef } from '../jsonSchema';
-import { isNumber, equals, isBoolean, isString, isDefined, isObject } from '../utils/objects';
-import { extendedRegExp, stringLength } from '../utils/strings';
-import { TextDocument, ASTNode, ObjectASTNode, ArrayASTNode, BooleanASTNode, NumberASTNode, StringASTNode, NullASTNode, PropertyASTNode, JSONPath, ErrorCode, Diagnostic, DiagnosticSeverity, Range, SchemaDraft } from '../jsonLanguageTypes';
+import { JSONSchema, JSONSchemaRef } from '../jsonSchema.js';
+import { isNumber, equals, isBoolean, isString, isDefined, isObject } from '../utils/objects.js';
+import { extendedRegExp, stringLength } from '../utils/strings.js';
+import { TextDocument, ASTNode, ObjectASTNode, ArrayASTNode, BooleanASTNode, NumberASTNode, StringASTNode, NullASTNode, PropertyASTNode, JSONPath, ErrorCode, Diagnostic, DiagnosticSeverity, Range, SchemaDraft } from '../jsonLanguageTypes.js';
 import { URI } from 'vscode-uri';
 
 import * as l10n from '@vscode/l10n';

diff --git a/src/services/configuration.ts b/src/services/configuration.ts
@@ -3,9 +3,9 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { ISchemaContributions } from './jsonSchemaService';
-import draft201909Flat from './schemas/draft-2019-09-flat';
-import draft202012Flat from './schemas/draft-2020-12-flat';
+import { ISchemaContributions } from './jsonSchemaService.js';
+import draft201909Flat from './schemas/draft-2019-09-flat.js';
+import draft202012Flat from './schemas/draft-2020-12-flat.js';
 
 import * as l10n from '@vscode/l10n';
 

diff --git a/src/services/jsonCompletion.ts b/src/services/jsonCompletion.ts
@@ -3,20 +3,20 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import * as Parser from '../parser/jsonParser';
+import * as Parser from '../parser/jsonParser.js';
 import * as Json from 'jsonc-parser';
-import * as SchemaService from './jsonSchemaService';
-import { JSONSchema, JSONSchemaRef } from '../jsonSchema';
-import { JSONWorkerContribution, CompletionsCollector, JSONCompletionItem } from '../jsonContributions';
-import { stringifyObject } from '../utils/json';
-import { endsWith, extendedRegExp } from '../utils/strings';
-import { isDefined } from '../utils/objects';
+import * as SchemaService from './jsonSchemaService.js';
+import { JSONSchema, JSONSchemaRef } from '../jsonSchema.js';
+import { JSONWorkerContribution, CompletionsCollector, JSONCompletionItem } from '../jsonContributions.js';
+import { stringifyObject } from '../utils/json.js';
+import { endsWith, extendedRegExp } from '../utils/strings.js';
+import { isDefined } from '../utils/objects.js';
 import {
 	PromiseConstructor,
 	ASTNode, ObjectASTNode, ArrayASTNode, PropertyASTNode, ClientCapabilities,
 	TextDocument,
 	CompletionItem, CompletionItemKind, CompletionList, Position, Range, TextEdit, InsertTextFormat, MarkupContent, MarkupKind
-} from '../jsonLanguageTypes';
+} from '../jsonLanguageTypes.js';
 
 import * as l10n from '@vscode/l10n';
 

diff --git a/src/services/jsonDocumentSymbols.ts b/src/services/jsonDocumentSymbols.ts
@@ -3,17 +3,17 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import * as Parser from '../parser/jsonParser';
-import * as Strings from '../utils/strings';
-import { colorFromHex } from '../utils/colors';
+import * as Parser from '../parser/jsonParser.js';
+import * as Strings from '../utils/strings.js';
+import { colorFromHex } from '../utils/colors.js';
 import * as l10n from '@vscode/l10n';
 
 import {
 	TextDocument, ColorInformation, ColorPresentation, Color, ASTNode, PropertyASTNode, DocumentSymbolsContext, Range, TextEdit,
 	SymbolInformation, SymbolKind, DocumentSymbol, Location
-} from "../jsonLanguageTypes";
+} from "../jsonLanguageTypes.js";
 
-import { IJSONSchemaService } from "./jsonSchemaService";
+import { IJSONSchemaService } from "./jsonSchemaService.js";
 
 export class JSONDocumentSymbols {
 

diff --git a/src/services/jsonFolding.ts b/src/services/jsonFolding.ts
@@ -4,7 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { createScanner, SyntaxKind, ScanError } from 'jsonc-parser';
-import { TextDocument, FoldingRangeKind, FoldingRange, FoldingRangesContext, Position } from '../jsonLanguageTypes';
+import { TextDocument, FoldingRangeKind, FoldingRange, FoldingRangesContext, Position } from '../jsonLanguageTypes.js';
 
 export function getFoldingRanges(document: TextDocument, context?: FoldingRangesContext): FoldingRange[] {
 	const ranges: FoldingRange[] = [];

diff --git a/src/services/jsonHover.ts b/src/services/jsonHover.ts
@@ -3,10 +3,10 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import * as Parser from '../parser/jsonParser';
-import * as SchemaService from './jsonSchemaService';
-import { JSONWorkerContribution } from '../jsonContributions';
-import { TextDocument, PromiseConstructor, Position, Range, Hover, MarkedString } from '../jsonLanguageTypes';
+import * as Parser from '../parser/jsonParser.js';
+import * as SchemaService from './jsonSchemaService.js';
+import { JSONWorkerContribution } from '../jsonContributions.js';
+import { TextDocument, PromiseConstructor, Position, Range, Hover, MarkedString } from '../jsonLanguageTypes.js';
 
 export class JSONHover {