typescript-eslint · Josh-Cena · Jul 20, 2024 · Jul 11, 2024 · Jul 11, 2024 · Jul 12, 2024
diff --git a/eslint.config.mjs b/eslint.config.mjs
@@ -216,6 +216,7 @@ export default tseslint.config(
       'operator-assignment': 'error',
       'prefer-arrow-callback': 'error',
       'prefer-const': 'error',
+      'prefer-object-spread': 'error',
       'prefer-rest-params': 'error',
 
       //

diff --git a/packages/eslint-plugin/src/rules/ban-types.ts b/packages/eslint-plugin/src/rules/ban-types.ts
@@ -207,11 +207,10 @@ export default createRule<Options, MessageIds>({
   create(context, [options]) {
     const extendDefaults = options.extendDefaults ?? true;
     const customTypes = options.types ?? {};
-    const types = Object.assign(
-      {},
-      extendDefaults ? defaultTypes : {},
-      customTypes,
-    );
+    const types = {
+      ...(extendDefaults && defaultTypes),
+      ...customTypes,
+    };
     const bannedTypes = new Map(
       Object.entries(types).map(([type, data]) => [removeSpaces(type), data]),
     );

diff --git a/packages/eslint-plugin/src/rules/indent.ts b/packages/eslint-plugin/src/rules/indent.ts
@@ -181,16 +181,17 @@ export default createRule<Options, MessageIds>({
       } as TSESTree.PropertyDefinition;
     }
 
-    return Object.assign({}, rules, {
+    return {
+      ...rules,
       // overwrite the base rule here so we can use our KNOWN_NODES list instead
-      '*:exit'(node: TSESTree.Node) {
+      '*:exit'(node: TSESTree.Node): void {
         // For nodes we care about, skip the default handling, because it just marks the node as ignored...
         if (!KNOWN_NODES.has(node.type)) {
           rules['*:exit'](node);
         }
       },
 
-      VariableDeclaration(node: TSESTree.VariableDeclaration) {
+      VariableDeclaration(node: TSESTree.VariableDeclaration): void {
         // https://github.com/typescript-eslint/typescript-eslint/issues/441
         if (node.declarations.length === 0) {
           return;
@@ -199,7 +200,7 @@ export default createRule<Options, MessageIds>({
         return rules.VariableDeclaration(node);
       },
 
-      TSAsExpression(node: TSESTree.TSAsExpression) {
+      TSAsExpression(node: TSESTree.TSAsExpression): void {
         // transform it to a BinaryExpression
         return rules['BinaryExpression, LogicalExpression']({
           type: AST_NODE_TYPES.BinaryExpression,
@@ -215,7 +216,7 @@ export default createRule<Options, MessageIds>({
         });
       },
 
-      TSConditionalType(node: TSESTree.TSConditionalType) {
+      TSConditionalType(node: TSESTree.TSConditionalType): void {
         // transform it to a ConditionalExpression
         return rules.ConditionalExpression({
           type: AST_NODE_TYPES.ConditionalExpression,
@@ -245,7 +246,7 @@ export default createRule<Options, MessageIds>({
 
       'TSEnumDeclaration, TSTypeLiteral'(
         node: TSESTree.TSEnumDeclaration | TSESTree.TSTypeLiteral,
-      ) {
+      ): void {
         // transform it to an ObjectExpression
         return rules['ObjectExpression, ObjectPattern']({
           type: AST_NODE_TYPES.ObjectExpression,
@@ -263,7 +264,9 @@ export default createRule<Options, MessageIds>({
         });
       },
 
-      TSImportEqualsDeclaration(node: TSESTree.TSImportEqualsDeclaration) {
+      TSImportEqualsDeclaration(
+        node: TSESTree.TSImportEqualsDeclaration,
+      ): void {
         // transform it to an VariableDeclaration
         // use VariableDeclaration instead of ImportDeclaration because it's essentially the same thing
         const { id, moduleReference } = node;
@@ -317,7 +320,7 @@ export default createRule<Options, MessageIds>({
         });
       },
 
-      TSIndexedAccessType(node: TSESTree.TSIndexedAccessType) {
+      TSIndexedAccessType(node: TSESTree.TSIndexedAccessType): void {
         // convert to a MemberExpression
         return rules['MemberExpression, JSXMemberExpression, MetaProperty']({
           type: AST_NODE_TYPES.MemberExpression,
@@ -333,7 +336,7 @@ export default createRule<Options, MessageIds>({
         });
       },
 
-      TSInterfaceBody(node: TSESTree.TSInterfaceBody) {
+      TSInterfaceBody(node: TSESTree.TSInterfaceBody): void {
         // transform it to an ClassBody
         return rules['BlockStatement, ClassBody']({
           type: AST_NODE_TYPES.ClassBody,
@@ -354,7 +357,7 @@ export default createRule<Options, MessageIds>({
 
       'TSInterfaceDeclaration[extends.length > 0]'(
         node: TSESTree.TSInterfaceDeclaration,
-      ) {
+      ): void {
         // transform it to a ClassDeclaration
         return rules[
           'ClassDeclaration[superClass], ClassExpression[superClass]'
@@ -379,7 +382,7 @@ export default createRule<Options, MessageIds>({
         });
       },
 
-      TSMappedType(node: TSESTree.TSMappedType) {
+      TSMappedType(node: TSESTree.TSMappedType): void {
         // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
         const squareBracketStart = context.sourceCode.getTokenBefore(
           node.typeParameter,
@@ -423,7 +426,7 @@ export default createRule<Options, MessageIds>({
         });
       },
 
-      TSModuleBlock(node: TSESTree.TSModuleBlock) {
+      TSModuleBlock(node: TSESTree.TSModuleBlock): void {
         // transform it to a BlockStatement
         return rules['BlockStatement, ClassBody']({
           type: AST_NODE_TYPES.BlockStatement,
@@ -436,7 +439,7 @@ export default createRule<Options, MessageIds>({
         });
       },
 
-      TSQualifiedName(node: TSESTree.TSQualifiedName) {
+      TSQualifiedName(node: TSESTree.TSQualifiedName): void {
         return rules['MemberExpression, JSXMemberExpression, MetaProperty']({
           type: AST_NODE_TYPES.MemberExpression,
           object: node.left as any,
@@ -451,7 +454,7 @@ export default createRule<Options, MessageIds>({
         });
       },
 
-      TSTupleType(node: TSESTree.TSTupleType) {
+      TSTupleType(node: TSESTree.TSTupleType): void {
         // transform it to an ArrayExpression
         return rules['ArrayExpression, ArrayPattern']({
           type: AST_NODE_TYPES.ArrayExpression,
@@ -464,7 +467,9 @@ export default createRule<Options, MessageIds>({
         });
       },
 
-      TSTypeParameterDeclaration(node: TSESTree.TSTypeParameterDeclaration) {
+      TSTypeParameterDeclaration(
+        node: TSESTree.TSTypeParameterDeclaration,
+      ): void {
         if (!node.params.length) {
           return;
         }
@@ -487,6 +492,6 @@ export default createRule<Options, MessageIds>({
           loc: node.loc,
         });
       },
-    });
+    };
   },
 });
diff --git a/packages/eslint-plugin/src/rules/no-extra-parens.ts b/packages/eslint-plugin/src/rules/no-extra-parens.ts
@@ -303,6 +303,6 @@ export default createRule<Options, MessageIds>({
         }
       },
     };
-    return Object.assign({}, rules, overrides);
+    return { ...rules, ...overrides };
   },
 });
diff --git a/packages/eslint-plugin/src/util/getFunctionHeadLoc.ts b/packages/eslint-plugin/src/util/getFunctionHeadLoc.ts
@@ -197,7 +197,7 @@ export function getFunctionHeadLoc(
   }
 
   return {
-    start: Object.assign({}, start),
-    end: Object.assign({}, end),
+    start: { ...start },
+    end: { ...end },
   };
 }
diff --git a/packages/parser/tests/test-utils/test-utils.ts b/packages/parser/tests/test-utils/test-utils.ts
@@ -10,7 +10,7 @@ const defaultConfig = {
   tokens: true,
   comment: true,
   errorOnUnknownASTType: true,
-  sourceType: 'module',
+  sourceType: 'module' as const,
 };
 
 /**
@@ -40,7 +40,7 @@ export function createSnapshotTestBlock(
   code: string,
   config: ParserOptions = {},
 ): () => void {
-  config = Object.assign({}, defaultConfig, config);
+  config = { ...defaultConfig, ...config };
 
   /**
    * @returns the AST object
@@ -72,7 +72,7 @@ export function createSnapshotTestBlock(
  * @param config The configuration object for the parser
  */
 export function testServices(code: string, config: ParserOptions = {}): void {
-  config = Object.assign({}, defaultConfig, config);
+  config = { ...defaultConfig, ...config };
 
   const services = parser.parseForESLint(code, config).services;
   expect(services).toBeDefined();

diff --git a/packages/rule-tester/src/RuleTester.ts b/packages/rule-tester/src/RuleTester.ts
@@ -399,19 +399,17 @@ export class RuleTester extends TestFramework {
       emitLegacyRuleAPIWarning(ruleName);
     }
 
-    this.#linter.defineRule(
-      ruleName,
-      Object.assign({}, rule, {
-        // Create a wrapper rule that freezes the `context` properties.
-        create(context: RuleContext<MessageIds, Options>) {
-          freezeDeeply(context.options);
-          freezeDeeply(context.settings);
-          freezeDeeply(context.parserOptions);
-
-          return (typeof rule === 'function' ? rule : rule.create)(context);
-        },
-      }),
-    );
+    this.#linter.defineRule(ruleName, {
+      ...rule,
+      // Create a wrapper rule that freezes the `context` properties.
+      create(context: RuleContext<MessageIds, Options>) {
+        freezeDeeply(context.options);
+        freezeDeeply(context.settings);
+        freezeDeeply(context.parserOptions);
+
+        return (typeof rule === 'function' ? rule : rule.create)(context);
+      },
+    });
 
     this.#linter.defineRules(this.#rules);
 

diff --git a/packages/utils/tests/eslint-utils/deepMerge.test.ts b/packages/utils/tests/eslint-utils/deepMerge.test.ts
@@ -38,7 +38,7 @@ describe('deepMerge', () => {
       },
     };
 
-    expect(ESLintUtils.deepMerge(a, b)).toStrictEqual(Object.assign({}, a, b));
+    expect(ESLintUtils.deepMerge(a, b)).toStrictEqual({ ...a, ...b });
   });
 
   it('deeply overwrites properties in the first one with the second', () => {
-Original file line number
+Diff line change
@@ Expand Up / @@ -303,6 +303,6 @@ export default createRule<Options, MessageIds>({ @@
             }
           },
         };
-        return Object.assign({}, rules, overrides);
+        return { ...rules, ...overrides };
       },
     });