typescript-eslint · JoshuaKGoldberg · Nov 12, 2023 · Oct 25, 2023 · Oct 25, 2023 · Nov 11, 2023
diff --git a/packages/typescript-estree/src/create-program/createDefaultProgram.ts b/packages/typescript-estree/src/create-program/createDefaultProgram.ts
@@ -23,7 +23,7 @@ function createDefaultProgram(
     parseSettings.filePath || 'unnamed file',
   );
 
-  if (parseSettings.projects?.length !== 1) {
+  if (parseSettings.projects.length !== 1) {
     return undefined;
   }
 

diff --git a/packages/typescript-estree/src/create-program/createProjectProgram.ts b/packages/typescript-estree/src/create-program/createProjectProgram.ts
@@ -58,7 +58,7 @@ function createProjectProgram(
   ];
   let hasMatchedAnError = false;
 
-  const extraFileExtensions = parseSettings.extraFileExtensions || [];
+  const { extraFileExtensions } = parseSettings;
 
   extraFileExtensions.forEach(extraExtension => {
     if (!extraExtension.startsWith('.')) {

diff --git a/packages/typescript-estree/src/getModifiers.ts b/packages/typescript-estree/src/getModifiers.ts
@@ -25,7 +25,7 @@ export function getModifiers(
 
   return (
     // @ts-expect-error intentional fallback for older TS versions
-    (node.modifiers as ts.Modifier[])?.filter(
+    (node.modifiers as ts.Modifier[] | undefined)?.filter(
       (m): m is ts.Modifier => !ts.isDecorator(m),
     )
   );
@@ -52,6 +52,6 @@ export function getDecorators(
 
   return (
     // @ts-expect-error intentional fallback for older TS versions
-    (node.decorators as ts.Node[])?.filter(ts.isDecorator)
+    (node.decorators as ts.Node[] | undefined)?.filter(ts.isDecorator)
   );
 }
diff --git a/packages/typescript-estree/src/node-utils.ts b/packages/typescript-estree/src/node-utils.ts
@@ -424,11 +424,12 @@ export function findFirstMatchingAncestor(
   node: ts.Node,
   predicate: (node: ts.Node) => boolean,
 ): ts.Node | undefined {
-  while (node) {
-    if (predicate(node)) {
-      return node;
+  let current: ts.Node | undefined = node;
+  while (current) {
+    if (predicate(current)) {
+      return current;
     }
-    node = node.parent;
+    current = current.parent;
   }
   return undefined;
 }
@@ -482,9 +483,7 @@ export function isComputedProperty(
 export function isOptional(node: {
   questionToken?: ts.QuestionToken;
 }): boolean {
-  return node.questionToken
-    ? node.questionToken.kind === SyntaxKind.QuestionToken
-    : false;
+  return !!node.questionToken;
 }
 
 /**
@@ -677,11 +676,7 @@ export function convertTokens(ast: ts.SourceFile): TSESTree.Token[] {
     }
 
     if (isToken(node) && node.kind !== SyntaxKind.EndOfFileToken) {
-      const converted = convertToken(node, ast);
-
-      if (converted) {
-        result.push(converted);
-      }
+      result.push(convertToken(node, ast));
     } else {
       node.getChildren(ast).forEach(walk);
     }
@@ -943,11 +938,10 @@ export function getNamespaceModifiers(
   let moduleDeclaration = node;
   while (
     (!modifiers || modifiers.length === 0) &&
-    ts.isModuleDeclaration(moduleDeclaration.parent) &&
-    moduleDeclaration.parent.name
+    ts.isModuleDeclaration(moduleDeclaration.parent)
   ) {
     const parentModifiers = getModifiers(moduleDeclaration.parent);
-    if (parentModifiers && parentModifiers?.length > 0) {
+    if (parentModifiers?.length) {
       modifiers = parentModifiers;
     }
     moduleDeclaration = moduleDeclaration.parent;

diff --git a/packages/typescript-estree/src/parseSettings/inferSingleRun.ts b/packages/typescript-estree/src/parseSettings/inferSingleRun.ts
@@ -20,7 +20,7 @@ export function inferSingleRun(options: TSESTreeOptions | undefined): boolean {
     options?.project == null ||
     // programs passed via options means the user should be managing the programs, so we shouldn't
     // be creating our own single-run programs accidentally
-    options?.programs != null
+    options.programs != null
   ) {
     return false;
   }
@@ -34,7 +34,7 @@ export function inferSingleRun(options: TSESTreeOptions | undefined): boolean {
   }
 
   // Currently behind a flag while we gather real-world feedback
-  if (options?.allowAutomaticSingleRunInference) {
+  if (options.allowAutomaticSingleRunInference) {
     if (
       // Default to single runs for CI processes. CI=true is set by most CI providers by default.
       process.env.CI === 'true' ||

diff --git a/packages/typescript-estree/src/parser.ts b/packages/typescript-estree/src/parser.ts
@@ -181,7 +181,7 @@ function parseAndGenerateServices<T extends TSESTreeOptions = TSESTreeOptions>(
   if (
     parseSettings.singleRun &&
     !parseSettings.programs &&
-    parseSettings.projects?.length > 0
+    parseSettings.projects.length > 0
   ) {
     parseSettings.programs = {
       *[Symbol.iterator](): Iterator<ts.Program> {
@@ -207,25 +207,22 @@ function parseAndGenerateServices<T extends TSESTreeOptions = TSESTreeOptions>(
    * Generate a full ts.Program or offer provided instances in order to be able to provide parser services, such as type-checking
    */
   const hasFullTypeInformation =
-    parseSettings.programs != null || parseSettings.projects?.length > 0;
+    parseSettings.programs != null || parseSettings.projects.length > 0;
 
-  if (options !== undefined) {
-    if (
-      typeof options.errorOnTypeScriptSyntacticAndSemanticIssues ===
-        'boolean' &&
-      options.errorOnTypeScriptSyntacticAndSemanticIssues
-    ) {
-      parseSettings.errorOnTypeScriptSyntacticAndSemanticIssues = true;
-    }
+  if (
+    typeof options.errorOnTypeScriptSyntacticAndSemanticIssues === 'boolean' &&
+    options.errorOnTypeScriptSyntacticAndSemanticIssues
+  ) {
+    parseSettings.errorOnTypeScriptSyntacticAndSemanticIssues = true;
+  }
 
-    if (
-      parseSettings.errorOnTypeScriptSyntacticAndSemanticIssues &&
-      !hasFullTypeInformation
-    ) {
-      throw new Error(
-        'Cannot calculate TypeScript semantic issues without a valid project.',
-      );
-    }
+  if (
+    parseSettings.errorOnTypeScriptSyntacticAndSemanticIssues &&
+    !hasFullTypeInformation
+  ) {
+    throw new Error(
+      'Cannot calculate TypeScript semantic issues without a valid project.',
+    );
   }
 
   /**

diff --git a/packages/typescript-estree/tests/lib/parse.test.ts b/packages/typescript-estree/tests/lib/parse.test.ts
@@ -135,7 +135,7 @@ describe('parseAndGenerateServices', () => {
         });
 
         expect(
-          parseResult.services.esTreeNodeToTSNodeMap?.has(
+          parseResult.services.esTreeNodeToTSNodeMap.has(
             parseResult.ast.body[0],
           ),
         ).toBe(setting);

diff --git a/packages/typescript-estree/tests/lib/semanticInfo.test.ts b/packages/typescript-estree/tests/lib/semanticInfo.test.ts
@@ -228,11 +228,11 @@ describe('semanticInfo', () => {
     expect(boundName.name).toBe('x');
 
     const tsBoundName =
-      parseResult.services.esTreeNodeToTSNodeMap?.get(boundName);
+      parseResult.services.esTreeNodeToTSNodeMap.get(boundName);
     expectToBeDefined(tsBoundName);
     expect(tsBoundName).toBeDefined();
 
-    expect(parseResult.services.tsNodeToESTreeNodeMap?.get(tsBoundName)).toBe(
+    expect(parseResult.services.tsNodeToESTreeNodeMap.get(tsBoundName)).toBe(
       boundName,
     );
   });

diff --git a/packages/typescript-estree/tools/test-utils.ts b/packages/typescript-estree/tools/test-utils.ts
@@ -106,7 +106,7 @@ export function omitDeep<T = UnknownObject>(
   > = {},
 ): UnknownObject {
   function shouldOmit(keyName: string, val: unknown): boolean {
-    if (keysToOmit?.length) {
+    if (keysToOmit.length) {
       return keysToOmit.some(
         keyConfig => keyConfig.key === keyName && keyConfig.predicate(val),
       );