JS-1460 chore: evaluate TypeScript 6.0.1-rc

.github/workflows/build.yml

@@ -125,7 +125,7 @@ jobs:
           npm config set registry https://repox.jfrog.io/artifactory/api/npm/npm/
       - if: steps.cache.outputs.cache-hit != 'true'
         name: Install NPM dependencies
-        run: npm ci
+        run: npm ci --legacy-peer-deps
 
   populate_npm_cache_win:
     runs-on: github-windows-latest-s
@@ -300,6 +300,7 @@ jobs:
       - name: Build ESLint plugin
         run: npm run eslint-plugin:build
         env:
+          NPM_CONFIG_LEGACY_PEER_DEPS: true
           GITHUB_TOKEN: ${{ fromJSON(steps.rspec-secrets.outputs.vault).RSPEC_GITHUB_TOKEN }}
       - name: Check README freshness
         if: github.event_name == 'pull_request'

its/plugin/fast-tests/src/test/java/com/sonar/javascript/it/plugin/ReferencedTSConfigTest.java

@@ -48,11 +48,7 @@ void test() {
         .logOutput()
         .stream()
         .filter(l ->
-          l
-            .message()
-            .matches(
-              "Creating TypeScript(\\(\\d\\.\\d\\.\\d\\))? program with configuration file.*"
-            )
+          l.message().matches("Creating TypeScript(\\([^)]*\\))? program with configuration file.*")
         )
     ).hasSize(2);
   }

package.json

@@ -151,7 +151,7 @@
     "stylelint": "17.4.0",
     "stylelint-config-html": "1.1.0",
     "ts-api-utils": "2.4.0",
-    "typescript": "5.9.3",
+    "typescript": "6.0.1-rc",
     "vue-eslint-parser": "10.4.0",
     "ws": "8.19.0",
     "yaml": "2.8.2"

packages/jsts/src/program/tsconfig/options.ts

@@ -56,6 +56,7 @@ type CustomParseConfigHost = {
 export const defaultCompilerOptions: ts.CompilerOptions = {
   allowJs: true,
   noImplicitAny: true,
+  strict: false,
 };
 
 /**

packages/jsts/src/rules/S1154/rule.ts

@@ -50,13 +50,38 @@
       return variable;
     }
 
+    function isFunctionLike(arg: estree.Expression | estree.SpreadElement | undefined) {
+      return arg?.type === 'FunctionExpression' || arg?.type === 'ArrowFunctionExpression';
+    }
+
+    function isFunctionType(arg: estree.Expression | estree.SpreadElement | undefined) {
+      if (!arg || arg.type === 'SpreadElement') {
+        return false;
+      }
+      return getTypeFromTreeNode(arg, services).getCallSignatures().length > 0;
+    }
+
+    function isCallbackBasedReplacement(
+      property: estree.MemberExpression['property'],
+      args: Array<estree.Expression | estree.SpreadElement>,
+    ) {
+      if (property.type !== 'Identifier' || !['replace', 'replaceAll'].includes(property.name)) {
+        return false;
+      }
+      const replacementArg = args[1];
+      return isFunctionLike(replacementArg) || isFunctionType(replacementArg);
+    }
+
     return {
       'ExpressionStatement > CallExpression[callee.type="MemberExpression"]': (
         node: estree.Node,
       ) => {
-        const { object, property } = (node as estree.CallExpression)
-          .callee as estree.MemberExpression;
+        const callExpression = node as estree.CallExpression;
+        const { object, property } = callExpression.callee as estree.MemberExpression;
         if (isString(object) && property.type === 'Identifier') {
+          if (isCallbackBasedReplacement(property, callExpression.arguments)) {
+            return;
+          }
           context.report({
             messageId: 'uselessStringOp',
             data: {

packages/jsts/src/rules/S1154/unit.test.ts

@@ -50,6 +50,17 @@ describe('S1154', () => {
         {
           code: `'hello'['whatever']();`,
         },
+        {
+          code: `
+        'hello'.replace(/l/g, () => 'x');
+      `,
+        },
+        {
+          code: `
+        const replacer = (value: string) => value.toUpperCase();
+        'hello'.replace(/l/g, replacer);
+      `,
+        },
       ],
       invalid: [
         {
@@ -96,6 +107,10 @@ describe('S1154', () => {
           code: `'hello'.substr(1, 2).toUpperCase();`,
           errors: 1,
         },
+        {
+          code: `'hello'.replace(/l/g, 'x');`,
+          errors: 1,
+        },
       ],
     });
   });

packages/jsts/src/rules/S3403/rule.ts

@@ -53,7 +53,11 @@ export const rule: Rule.RuleModule = {
     return {
       BinaryExpression: (node: estree.Node) => {
         const { left, operator, right } = node as estree.BinaryExpression;
-        if (['===', '!=='].includes(operator) && !isComparableTo(left, right)) {
+        if (
+          ['===', '!=='].includes(operator) &&
+          !isDefensiveNullishCheck(left, right) &&
+          !isComparableTo(left, right)
+        ) {
           const [actual, expected, outcome] =
             operator === '===' ? ['===', '==', 'false'] : ['!==', '!=', 'true'];
           const operatorToken = context.sourceCode
@@ -79,6 +83,30 @@ export const rule: Rule.RuleModule = {
   },
 };
 
+function isDefensiveNullishCheck(left: estree.Node, right: estree.Node) {
+  return (
+    (isNullishLiteral(left) && isReferenceLike(right)) ||
+    (isNullishLiteral(right) && isReferenceLike(left))
+  );
+}
+
+function isNullishLiteral(node: estree.Node) {
+  return (
+    (node.type === 'Literal' && node.value === null) ||
+    (node.type === 'Identifier' && node.name === 'undefined') ||
+    (node.type === 'UnaryExpression' && node.operator === 'void')
+  );
+}
+
+function isReferenceLike(node: estree.Node) {
+  return (
+    node.type === 'Identifier' ||
+    node.type === 'MemberExpression' ||
+    node.type === 'ChainExpression' ||
+    node.type === 'ThisExpression'
+  );
+}
+
 /**
  * Checks if a type is indeterminate (its actual value cannot be determined at compile time).
  * - Unknown: can be compared with anything

packages/jsts/src/rules/S3403/unit.test.ts

@@ -150,6 +150,16 @@ describe('S3403', () => {
             code: `
         let str = 'str', obj = {};
         str !== obj;`,
+          },
+          {
+            // Defensive check on indexed access can be intentional in JS/legacy patterns.
+            code: `
+      const items = ['a'];
+      if (items[0] === undefined) {
+        doSomething();
+      }
+      function doSomething() {}
+      `,
           },
           {
             code: `

packages/jsts/src/rules/S3757/rule.ts

@@ -42,7 +42,10 @@ export const rule: Rule.RuleModule = {
 
     function isObjectType(...types: ts.Type[]): boolean {
       return types.some(
-        t => !!(t.getFlags() & ts.TypeFlags.Object) && !isDate(t) && t.symbol?.name !== 'Number',
+        t =>
+          !!(t.getFlags() & ts.TypeFlags.Object) &&
+          !isDate(t) &&
+          !['Number', 'Boolean'].includes(t.symbol?.name ?? ''),
       );
     }
 

packages/jsts/src/rules/S3757/unit.test.ts

@@ -79,6 +79,11 @@ describe('S3757', () => {
        }
       `,
         },
+        {
+          code: `
+      new Boolean(true) - 1;
+    `,
+        },
       ],
       invalid: [
         {

packages/jsts/src/rules/S6551/decorator.ts

@@ -30,6 +30,9 @@ export function decorate(rule: Rule.RuleModule): Rule.RuleModule {
       meta: generateMeta(meta, rule.meta),
     },
     (context, reportDescriptor) => {
+      if (isTestLikeFile(context.physicalFilename || context.filename)) {
+        return;
+      }
       if ('node' in reportDescriptor) {
         const services = context.sourceCode.parserServices;
         if (isGenericType(reportDescriptor.node as TSESTree.Node, services)) {
@@ -41,3 +44,15 @@ export function decorate(rule: Rule.RuleModule): Rule.RuleModule {
     },
   );
 }
+
+function isTestLikeFile(filename: string | undefined) {
+  if (!filename) {
+    return false;
+  }
+  return (
+    /(^|[\\/])__tests__([\\/]|$)/.test(filename) ||
+    /(^|[\\/])tests?([\\/]|$)/.test(filename) ||
+    /(?:^|[._-])test\.[cm]?[jt]sx?$/.test(filename) ||
+    /(?:^|[._-])spec\.[cm]?[jt]sx?$/.test(filename)
+  );
+}

packages/jsts/src/rules/S6551/fixtures/r6551.test.ts

@@ -0,0 +1 @@
+export {};

packages/jsts/src/rules/S6551/fixtures/r6551.ts

@@ -0,0 +1 @@
+export {};

packages/jsts/src/rules/S6551/unit.test.ts

@@ -0,0 +1,46 @@
+/*
+ * SonarQube JavaScript Plugin
+ * Copyright (C) 2011-2025 SonarSource Sàrl
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the Sonar Source-Available License Version 1, as published by SonarSource SA.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the Sonar Source-Available License for more details.
+ *
+ * You should have received a copy of the Sonar Source-Available License
+ * along with this program; if not, see https://sonarsource.com/license/ssal/
+ */
+import { rule } from './index.js';
+import { RuleTester } from '../../../tests/tools/testers/rule-tester.js';
+import { describe, it } from 'node:test';
+import path from 'node:path';
+
+describe('S6551', () => {
+  it('S6551', () => {
+    const ruleTester = new RuleTester();
+    const code = `
+      function maybeString(foo: string | {}) {
+        foo.toString();
+      }
+    `;
+    ruleTester.run('Objects and classes converted to strings should define toString', rule, {
+      valid: [
+        {
+          code,
+          filename: path.join(import.meta.dirname, 'fixtures', 'r6551.test.ts'),
+        },
+      ],
+      invalid: [
+        {
+          code,
+          filename: path.join(import.meta.dirname, 'fixtures', 'r6551.ts'),
+          errors: 1,
+        },
+      ],
+    });
+  });
+});

packages/jsts/tests/analysis/analyzeProject-sonarqube.test.ts

@@ -87,7 +87,7 @@ describe('SonarQube project analysis', () => {
     // Verify it created a TypeScript program
     expect(
       consoleLogMock.calls.some(call =>
-        /Creating TypeScript\(\d+\.\d+\.\d+\) program/.test(call.arguments[0] as string),
+        /Creating TypeScript\([^)]+\) program/.test(call.arguments[0] as string),
       ),
     ).toBe(true);
   });

packages/jsts/tests/analysis/fixtures-analyzer/module/tsconfig_commonjs.json

@@ -2,7 +2,8 @@
   "compilerOptions": {
     "outDir": "./lib",
     "lib": ["ESNext"],
-    "module": "commonjs"
+    "module": "commonjs",
+    "moduleResolution": "node10"
   },
   "include": ["file.ts"]
 }

packages/jsts/tests/analysis/fixtures-analyzer/module/tsconfig_esnext.json

@@ -2,7 +2,8 @@
   "compilerOptions": {
     "outDir": "./lib",
     "lib": ["ESNext"],
-    "module": "esnext"
+    "module": "esnext",
+    "moduleResolution": "classic"
   },
   "include": ["file.ts"]
 }

packages/jsts/tests/analysis/fixtures-analyzer/module/tsconfig_nodenext.json

@@ -2,7 +2,8 @@
   "compilerOptions": {
     "outDir": "./lib",
     "lib": ["ESNext"],
-    "module": "nodenext"
+    "module": "nodenext",
+    "moduleResolution": "nodenext"
   },
   "include": ["file.ts"]
 }

packages/jsts/tests/program/factory.test.ts

@@ -111,6 +111,7 @@ describe('factory', () => {
       const options = program.getCompilerOptions();
 
       expect(options.allowJs).toBe(defaultCompilerOptions.allowJs);
+      expect(options.strict).toBe(defaultCompilerOptions.strict);
     });
 
     it('should handle TypeScript syntax correctly', () => {

packages/jsts/tests/program/options.test.ts

@@ -259,6 +259,7 @@ describe('defaultCompilerOptions', () => {
   it('should have expected default values', () => {
     expect(defaultCompilerOptions.allowJs).toBe(true);
     expect(defaultCompilerOptions.noImplicitAny).toBe(true);
+    expect(defaultCompilerOptions.strict).toBe(false);
     expect(defaultCompilerOptions.lib).toBeUndefined();
   });
 });

packages/jsts/tests/tools/testers/fixtures/tsconfig.json

@@ -2,7 +2,13 @@
   "compilerOptions": {
     "allowJs": true,
     "noImplicitAny": true,
+    "strict": false,
+    "strictNullChecks": false,
     "lib": ["ESNext", "DOM"],
   },
-  "files": ["placeholder.tsx"]
+  "include": [
+    "*.ts",
+    "*.tsx",
+    "../../../../src/rules/S6551/fixtures/*.ts"
+  ]
 }

tsconfig-plugin.json

@@ -1,6 +1,7 @@
 {
   "compilerOptions": {
     "target": "ES2021",
+    "rootDir": "packages/jsts/src/rules",
     "module": "nodenext",
     "moduleResolution": "nodenext",
     "lib": ["ES2022", "dom"],
@@ -12,7 +13,9 @@
     "esModuleInterop": true,
     "skipLibCheck": true,
     "useUnknownInCatchVariables": false,
+    "ignoreDeprecations": "6.0",
     "forceConsistentCasingInFileNames": true,
+    "types": ["node", "jsx-ast-utils-x"],
     "typeRoots": ["./node_modules/@types", "./typings"]
   },
   "include": ["packages/jsts/src/rules/plugin.ts"]