typescript-eslint · JoshuaKGoldberg · Sep 4, 2024 · Aug 20, 2024 · Aug 20, 2024 · Aug 20, 2024
diff --git a/eslint.config.mjs b/eslint.config.mjs
@@ -332,6 +332,7 @@ export default tseslint.config(
       'unicorn/prefer-export-from': 'error',
       'unicorn/prefer-node-protocol': 'error',
       'unicorn/prefer-regexp-test': 'error',
+      'unicorn/prefer-spread': 'error',
       'unicorn/prefer-string-replace-all': 'error',
       'unicorn/prefer-structured-clone': 'error',
     },

diff --git a/packages/ast-spec/tests/fixtures.test.ts b/packages/ast-spec/tests/fixtures.test.ts
@@ -339,16 +339,12 @@ describe('AST Fixtures', () => {
 
   // once we've run all the tests, snapshot the list of fixtures that have differences for easy reference
   it('List fixtures with AST differences', () => {
-    expect(
-      Array.from(fixturesWithASTDifferences).sort(),
-    ).toMatchSpecificSnapshot(
+    expect([...fixturesWithASTDifferences].sort()).toMatchSpecificSnapshot(
       path.resolve(__dirname, 'fixtures-with-differences-ast.shot'),
     );
   });
   it('List fixtures with Token differences', () => {
-    expect(
-      Array.from(fixturesWithTokenDifferences).sort(),
-    ).toMatchSpecificSnapshot(
+    expect([...fixturesWithTokenDifferences].sort()).toMatchSpecificSnapshot(
       path.resolve(__dirname, 'fixtures-with-differences-tokens.shot'),
     );
   });
@@ -357,7 +353,7 @@ describe('AST Fixtures', () => {
       Object.fromEntries(
         Object.entries(fixturesWithErrorDifferences).map(([key, value]) => [
           key,
-          Array.from(value).sort(),
+          [...value].sort(),
         ]),
       ),
     ).toMatchSpecificSnapshot(
@@ -366,7 +362,7 @@ describe('AST Fixtures', () => {
   });
   it('List fixtures we expect babel to not support', () => {
     expect(
-      Array.from(fixturesConfiguredToExpectBabelToNotSupport).sort(),
+      [...fixturesConfiguredToExpectBabelToNotSupport].sort(),
     ).toMatchSpecificSnapshot(
       path.resolve(__dirname, 'fixtures-without-babel-support.shot'),
     );

diff --git a/packages/ast-spec/tests/util/serializers/Node.ts b/packages/ast-spec/tests/util/serializers/Node.ts
@@ -22,7 +22,7 @@ function sortKeys<Node extends TSESTree.Node>(
     keySet.delete('interpreter');
   }
 
-  return Array.from(keySet).sort((a, b) =>
+  return [...keySet].sort((a, b) =>
     a.localeCompare(b),
   ) as (keyof typeof node)[];
 }

diff --git a/packages/eslint-plugin/src/rules/consistent-type-exports.ts b/packages/eslint-plugin/src/rules/consistent-type-exports.ts
@@ -291,7 +291,7 @@ function* fixSeparateNamedExports(
 ): IterableIterator<TSESLint.RuleFix> {
   const { node, typeBasedSpecifiers, inlineTypeSpecifiers, valueSpecifiers } =
     report;
-  const typeSpecifiers = typeBasedSpecifiers.concat(inlineTypeSpecifiers);
+  const typeSpecifiers = [...typeBasedSpecifiers, ...inlineTypeSpecifiers];
   const source = getSourceFromExport(node);
   const specifierNames = typeSpecifiers.map(getSpecifierText).join(', ');
 

diff --git a/packages/eslint-plugin/src/rules/member-ordering.ts b/packages/eslint-plugin/src/rules/member-ordering.ts
@@ -509,7 +509,7 @@ function getRankOrder(
   orderConfig: MemberType[],
 ): number {
   let rank = -1;
-  const stack = memberGroups.slice(); // Get a copy of the member groups
+  const stack = [...memberGroups]; // Get a copy of the member groups
 
   while (stack.length > 0 && rank === -1) {
     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion

diff --git a/packages/eslint-plugin/src/rules/no-shadow.ts b/packages/eslint-plugin/src/rules/no-shadow.ts
@@ -645,7 +645,7 @@ export default createRule<Options, MessageIds>({
     return {
       'Program:exit'(node): void {
         const globalScope = context.sourceCode.getScope(node);
-        const stack = globalScope.childScopes.slice();
+        const stack = [...globalScope.childScopes];
 
         while (stack.length) {
           // eslint-disable-next-line @typescript-eslint/no-non-null-assertion

diff --git a/packages/eslint-plugin/src/rules/prefer-function-type.ts b/packages/eslint-plugin/src/rules/prefer-function-type.ts
@@ -108,9 +108,10 @@ export default createRule({
               const text = context.sourceCode
                 .getText()
                 .slice(start, member.range[1]);
-              const comments = context.sourceCode
-                .getCommentsBefore(member)
-                .concat(context.sourceCode.getCommentsAfter(member));
+              const comments = [
+                ...context.sourceCode.getCommentsBefore(member),
+                ...context.sourceCode.getCommentsAfter(member),
+              ];
               let suggestion = `${text.slice(0, colonPos)} =>${text.slice(
                 colonPos + 1,
               )}`;

diff --git a/packages/eslint-plugin/src/rules/prefer-readonly.ts b/packages/eslint-plugin/src/rules/prefer-readonly.ts
@@ -460,8 +460,8 @@ class ClassScope {
     });
 
     return [
-      ...Array.from(this.privateModifiableMembers.values()),
-      ...Array.from(this.privateModifiableStatics.values()),
+      ...this.privateModifiableMembers.values(),
+      ...this.privateModifiableStatics.values(),
     ];
   }
 }
diff --git a/packages/eslint-plugin/src/rules/unified-signatures.ts b/packages/eslint-plugin/src/rules/unified-signatures.ts
@@ -515,7 +515,7 @@ export default createRule<Options, MessageIds>({
         'checkScope() called without a current scope',
       );
       const failures = checkOverloads(
-        Array.from(scope.overloads.values()),
+        [...scope.overloads.values()],
         scope.typeParameters,
       );
       addFailures(failures);

diff --git a/packages/rule-schema-to-typescript-types/src/generateType.ts b/packages/rule-schema-to-typescript-types/src/generateType.ts
@@ -38,7 +38,7 @@ export function generateType(schema: JSONSchema4, refMap: RefMap): AST {
       throw new UnexpectedError(
         `Could not find definition for $ref ${
           schema.$ref
-        }.\nAvailable refs:\n${Array.from(refMap.keys()).join('\n')})`,
+        }.\nAvailable refs:\n${[...refMap.keys()].join('\n')})`,
         schema,
       );
     }

diff --git a/packages/rule-schema-to-typescript-types/src/optimizeAST.ts b/packages/rule-schema-to-typescript-types/src/optimizeAST.ts
@@ -44,7 +44,7 @@ export function optimizeAST(ast: AST | null): void {
       for (const element of elements) {
         uniqueElementsMap.set(JSON.stringify(element), element);
       }
-      const uniqueElements = Array.from(uniqueElementsMap.values());
+      const uniqueElements = [...uniqueElementsMap.values()];
 
       // @ts-expect-error -- purposely overwriting the property with a flattened list
       ast.elements = uniqueElements;

diff --git a/packages/rule-schema-to-typescript-types/src/printAST.ts b/packages/rule-schema-to-typescript-types/src/printAST.ts
@@ -42,7 +42,7 @@ function printAST(ast: AST): CodeWithComments {
       const code = printAndMaybeParenthesise(ast.elementType);
       return {
         code: `${code.code}[]`,
-        commentLines: ast.commentLines.concat(code.commentLines),
+        commentLines: [...ast.commentLines, ...code.commentLines],
       };
     }
 

diff --git a/packages/rule-tester/src/utils/flat-config-schema.ts b/packages/rule-tester/src/utils/flat-config-schema.ts
@@ -122,7 +122,7 @@ function normalizeRuleOptions(
   ruleOptions: SharedConfig.RuleLevel | SharedConfig.RuleLevelAndOptions,
 ): SharedConfig.RuleLevelAndOptions {
   const finalOptions = Array.isArray(ruleOptions)
-    ? ruleOptions.slice(0)
+    ? [...ruleOptions]
     : [ruleOptions];
 
   finalOptions[0] = ruleSeverities.get(

diff --git a/packages/scope-manager/src/ScopeManager.ts b/packages/scope-manager/src/ScopeManager.ts
@@ -56,7 +56,7 @@ class ScopeManager {
       scope.childScopes.forEach(recurse);
     }
     this.scopes.forEach(recurse);
-    return Array.from(variables).sort((a, b) => a.$id - b.$id);
+    return [...variables].sort((a, b) => a.$id - b.$id);
   }
 
   constructor(options: ScopeManagerOptions) {

diff --git a/packages/scope-manager/tests/fixtures.test.ts b/packages/scope-manager/tests/fixtures.test.ts
@@ -125,7 +125,7 @@ function nestDescribe(
 
         if (type[1] && !type[1].has(value)) {
           throw new Error(
-            `Expected value for ${key} to be one of (${Array.from(type[1]).join(
+            `Expected value for ${key} to be one of (${[...type[1]].join(
               ' | ',
             )}), but got ${value as string}`,
           );

diff --git a/packages/typescript-estree/src/convert.ts b/packages/typescript-estree/src/convert.ts
@@ -1984,9 +1984,9 @@
                 );
                 break;
               case SyntaxKind.NamedImports:
-                result.specifiers = result.specifiers.concat(
-                  node.importClause.namedBindings.elements.map(el =>
-                    this.convertChild(el),
+                result.specifiers.push(
+                  ...node.importClause.namedBindings.elements.map(
+                    el => this.convertChild(el) as TSESTree.ImportClause,
                   ),
                 );
                 break;
@@ -2165,7 +2165,7 @@
             left.type === AST_NODE_TYPES.SequenceExpression &&
             node.left.kind !== SyntaxKind.ParenthesizedExpression
           ) {
-            result.expressions = result.expressions.concat(left.expressions);
+            result.expressions.push(...left.expressions);
           } else {
             result.expressions.push(left);
           }

diff --git a/packages/typescript-estree/src/create-program/createProjectProgramError.ts b/packages/typescript-estree/src/create-program/createProjectProgramError.ts
@@ -35,7 +35,7 @@ function getErrorStart(
   describedFilePath: string,
   parseSettings: ParseSettings,
 ): string {
-  const relativeProjects = Array.from(parseSettings.projects.values()).map(
+  const relativeProjects = [...parseSettings.projects.values()].map(
     projectFile => describeFilePath(projectFile, parseSettings.tsconfigRootDir),
   );
 

diff --git a/packages/typescript-estree/src/create-program/getWatchProgramsForProjects.ts b/packages/typescript-estree/src/create-program/getWatchProgramsForProjects.ts
@@ -320,7 +320,7 @@ function createWatchProgram(
         path,
         !extensions
           ? undefined
-          : extensions.concat(parseSettings.extraFileExtensions),
+          : [...extensions, ...parseSettings.extraFileExtensions],
         exclude,
         include,
         depth,

diff --git a/packages/typescript-estree/src/getModifiers.ts b/packages/typescript-estree/src/getModifiers.ts
@@ -17,7 +17,7 @@ export function getModifiers(
     if (includeIllegalModifiers || ts.canHaveModifiers(node)) {
       // eslint-disable-next-line @typescript-eslint/no-deprecated -- this is safe as it's guarded
       const modifiers = ts.getModifiers(node as ts.HasModifiers);
-      return modifiers ? Array.from(modifiers) : undefined;
+      return modifiers ? [...modifiers] : undefined;
     }
 
     return undefined;
@@ -44,7 +44,7 @@ export function getDecorators(
     if (includeIllegalDecorators || ts.canHaveDecorators(node)) {
       // eslint-disable-next-line @typescript-eslint/no-deprecated -- this is safe as it's guarded
       const decorators = ts.getDecorators(node as ts.HasDecorators);
-      return decorators ? Array.from(decorators) : undefined;
+      return decorators ? [...decorators] : undefined;
     }
 
     return undefined;

diff --git a/packages/typescript-estree/src/parseSettings/resolveProjectList.ts b/packages/typescript-estree/src/parseSettings/resolveProjectList.ts
@@ -103,14 +103,12 @@ export function resolveProjectList(
   }
 
   const uniqueCanonicalProjectPaths = new Map(
-    nonGlobProjects
-      .concat(globProjectPaths)
-      .map(project => [
-        getCanonicalFileName(
-          ensureAbsolutePath(project, options.tsconfigRootDir),
-        ),
+    [...nonGlobProjects, ...globProjectPaths].map(project => [
+      getCanonicalFileName(
         ensureAbsolutePath(project, options.tsconfigRootDir),
-      ]),
+      ),
+      ensureAbsolutePath(project, options.tsconfigRootDir),
+    ]),
   );
 
   log(

diff --git a/packages/typescript-estree/src/parseSettings/warnAboutTSVersion.ts b/packages/typescript-estree/src/parseSettings/warnAboutTSVersion.ts
@@ -16,9 +16,7 @@ const SUPPORTED_PRERELEASE_RANGES: string[] = [];
 const ACTIVE_TYPESCRIPT_VERSION = ts.version;
 const isRunningSupportedTypeScriptVersion = semver.satisfies(
   ACTIVE_TYPESCRIPT_VERSION,
-  [SUPPORTED_TYPESCRIPT_VERSIONS]
-    .concat(SUPPORTED_PRERELEASE_RANGES)
-    .join(' || '),
+  [SUPPORTED_TYPESCRIPT_VERSIONS, ...SUPPORTED_PRERELEASE_RANGES].join(' || '),
 );
 
 let warnedAboutTSVersion = false;

diff --git a/packages/typescript-estree/src/useProgramFromProjectService.ts b/packages/typescript-estree/src/useProgramFromProjectService.ts
@@ -87,7 +87,7 @@ function openClientFileFromProjectService(
       serviceSettings.maximumDefaultProjectFileMatchCount
     ) {
       const filePrintLimit = 20;
-      const filesToPrint = Array.from(defaultProjectMatchedFiles).slice(
+      const filesToPrint = [...defaultProjectMatchedFiles].slice(
         0,
         filePrintLimit,
       );

diff --git a/packages/utils/src/eslint-utils/deepMerge.ts b/packages/utils/src/eslint-utils/deepMerge.ts
@@ -20,10 +20,10 @@ export function deepMerge(
   second: ObjectLike = {},
 ): Record<string, unknown> {
   // get the unique set of keys across both objects
-  const keys = new Set(Object.keys(first).concat(Object.keys(second)));
+  const keys = new Set([...Object.keys(first), ...Object.keys(second)]);
 
   return Object.fromEntries(
-    Array.from(keys, key => {
+    [...keys].map(key => {
       const firstHasKey = key in first;
       const secondHasKey = key in second;
       const firstValue = first[key];

diff --git a/packages/website-eslint/src/mock/path.js b/packages/website-eslint/src/mock/path.js
@@ -167,14 +167,10 @@ export function relative(from, to) {
     }
   }
 
-  let outputParts = [];
-  for (let i = samePartsLength; i < fromParts.length; i++) {
-    outputParts.push('..');
-  }
-
-  outputParts = outputParts.concat(toParts.slice(samePartsLength));
-
-  return outputParts.join('/');
+  return [
+    ...Array(fromParts.length - samePartsLength).fill('..'),
+    ...toParts.slice(samePartsLength),
+  ].join('/');
 }
 
 export const sep = '/';

diff --git a/packages/website/src/components/config/ConfigTypeScript.tsx b/packages/website/src/components/config/ConfigTypeScript.tsx
@@ -50,7 +50,7 @@ function ConfigTypeScript(props: ConfigTypeScriptProps): React.JSX.Element {
               key: item.name,
               type: 'string',
               label: item.description.message,
-              enum: ['', ...Array.from<string>(item.type.keys())],
+              enum: ['', ...item.type.keys()],
             });
           }
           return group;

diff --git a/packages/website/src/components/editor/LoadedEditor.tsx b/packages/website/src/components/editor/LoadedEditor.tsx
@@ -155,7 +155,7 @@ export const LoadedEditor: React.FC<LoadedEditorProps> = ({
       enableSchemaRequest: false,
       allowComments: true,
       schemas: [
-        ...Array.from(webLinter.rules.values()).map(rule => ({
+        ...[...webLinter.rules.values()].map(rule => ({
           uri: createRuleUri(rule.name),
           schema: getRuleJsonSchemaWithErrorLevel(rule.name, rule.schema),
         })),

diff --git a/packages/website/src/components/editor/useSandboxServices.ts b/packages/website/src/components/editor/useSandboxServices.ts
@@ -120,10 +120,13 @@ export const useSandboxServices = (
         );
 
         onLoaded(
-          Array.from(webLinter.rules.values()),
-          Array.from(
-            new Set([...sandboxInstance.supportedVersions, window.ts.version]),
-          )
+          [...webLinter.rules.values()],
+          [
+            ...new Set([
+              ...sandboxInstance.supportedVersions,
+              window.ts.version,
+            ]),
+          ]
             .filter(item =>
               semverSatisfies(item, rootPackageJson.devDependencies.typescript),
             )

diff --git a/packages/website/src/components/lib/jsonSchema.ts b/packages/website/src/components/lib/jsonSchema.ts
@@ -189,15 +189,15 @@ export function getTypescriptJsonSchema(): JSONSchema4 {
           value = {
             description: item.description.message,
             items: {
-              enum: Array.from(item.element.type.keys()),
+              enum: [...item.element.type.keys()],
               type: 'string',
             },
             type: 'array',
           };
         } else if (item.type instanceof Map) {
           value = {
             description: item.description.message,
-            enum: Array.from(item.type.keys()),
+            enum: [...item.type.keys()],
             type: 'string',
           };
         }

diff --git a/packages/website/src/components/linter/createLinter.ts b/packages/website/src/components/linter/createLinter.ts
@@ -182,7 +182,7 @@ export function createLinter(
   applyTSConfig('/tsconfig.json');
 
   return {
-    configs: Array.from(configs.keys()),
+    configs: [...configs.keys()],
     onLint: onLint.register,
     onParse: onParse.register,
     rules,

diff --git a/packages/website/src/components/linter/createParser.ts b/packages/website/src/components/linter/createParser.ts
@@ -28,7 +28,7 @@ export function createParser(
   ): tsvfs.VirtualTypeScriptEnvironment => {
     return vfs.createVirtualTypeScriptEnvironment(
       system,
-      Array.from(registeredFiles),
+      [...registeredFiles],
       window.ts,
       compilerOptions,
     );

diff --git a/packages/website/src/theme/NotFound/Content/index.tsx b/packages/website/src/theme/NotFound/Content/index.tsx
@@ -13,7 +13,7 @@ export default function NotFound(): React.JSX.Element {
           <h1 className={styles.title}>
             <div className={styles.code}>$ npx eslint .</div>
             <strong>
-              {`'${location.pathname}'`.split('').map((letter, i) => (
+              {[...`'${location.pathname}'`].map((letter, i) => (
                 <span className={styles.word} key={i}>
                   {letter}
                 </span>

diff --git a/tools/scripts/generate-lib.mts b/tools/scripts/generate-lib.mts
@@ -237,7 +237,7 @@ async function main(): Promise<void> {
 
     if (requiredBaseImports.size > 0) {
       imports.push(
-        `import {${Array.from(requiredBaseImports)
+        `import {${[...requiredBaseImports]
           .sort()
           .join(',')}} from './${BASE_CONFIG_MODULE_NAME}';`,
       );
@@ -288,9 +288,7 @@ async function main(): Promise<void> {
   // generate a string union type for the lib names
 
   const libUnionCode = [
-    `type Lib = ${Array.from(libMap.keys())
-      .map(k => `'${k}'`)
-      .join(' | ')};`,
+    `type Lib = ${[...libMap.keys()].map(k => `'${k}'`).join(' | ')};`,
     '',
     'export { Lib };',
   ];