fix(iku): Add TypeAliasDeclaration detection and fix block scope logic

4 files changed, 141 insertions, 40 deletions

diff --git a/packages/iku/src/checker.test.ts b/packages/iku/src/checker.test.ts
index 457d956..3116eb6 100644
--- a/packages/iku/src/checker.test.ts
+++ b/packages/iku/src/checker.test.ts
@@ -16,8 +16,7 @@ function createTempFile(content: string): string {
 function cleanupTempFile(filePath: string): void {
 	try {
 		unlinkSync(filePath);
-	} catch {
-	}
+	} catch {}
 }
 
 describe("checkFile", () => {
@@ -68,7 +67,9 @@ const b = 2;
 
 			cleanupTempFile(filePath);
 			expect(errors).toHaveLength(1);
-			expect(errors[0]).toContain("Unnecessary blank line between same statement types");
+			expect(errors[0]).toContain(
+				"Unnecessary blank line between same statement types",
+			);
 		});
 		it("passes for consecutive expression statements without blank lines", () => {
 			const content = `console.log("a");
@@ -105,7 +106,9 @@ console.log(a);
 
 			cleanupTempFile(filePath);
 			expect(errors).toHaveLength(1);
-			expect(errors[0]).toContain("Missing blank line between different statement types");
+			expect(errors[0]).toContain(
+				"Missing blank line between different statement types",
+			);
 		});
 		it("requires blank line between variable declaration and return", () => {
 			const content = `function test() {
@@ -133,7 +136,7 @@ console.log(a);
 
 			cleanupTempFile(filePath);
 			expect(errors).toHaveLength(1);
-			expect(errors[0]).toContain("expression -> if");
+			expect(errors[0]).toContain("Missing blank line around scoped block");
 		});
 	});
 	describe("scoped blocks", () => {
@@ -171,7 +174,7 @@ console.log(a);
 
 			cleanupTempFile(filePath);
 			expect(errors).toHaveLength(1);
-			expect(errors[0]).toContain("Missing blank line between scoped blocks of same type");
+			expect(errors[0]).toContain("Missing blank line around scoped block");
 		});
 		it("passes when scoped for loops have blank lines between them", () => {
 			const content = `function test(items: number[]) {
@@ -205,7 +208,7 @@ console.log(a);
 
 			cleanupTempFile(filePath);
 			expect(errors).toHaveLength(1);
-			expect(errors[0]).toContain("Missing blank line between scoped blocks of same type");
+			expect(errors[0]).toContain("Missing blank line around scoped block");
 		});
 	});
 	describe("nested blocks", () => {
@@ -290,7 +293,9 @@ const b = 2;
 			const errors = checkFile(filePath);
 
 			cleanupTempFile(filePath);
-			expect(errors.some((error) => error.includes("Comment detected"))).toBe(true);
+			expect(errors.some((error) => error.includes("Comment detected"))).toBe(
+				true,
+			);
 		});
 		it("detects multi-line comments by default", () => {
 			const content = `const a = 1;
@@ -302,7 +307,9 @@ const b = 2;
 			const errors = checkFile(filePath);
 
 			cleanupTempFile(filePath);
-			expect(errors.some((error) => error.includes("Comment detected"))).toBe(true);
+			expect(errors.some((error) => error.includes("Comment detected"))).toBe(
+				true,
+			);
 		});
 		it("detects trailing comments by default", () => {
 			const content = `const a = 1; // trailing comment
@@ -311,7 +318,9 @@ const b = 2;
 			const errors = checkFile(filePath);
 
 			cleanupTempFile(filePath);
-			expect(errors.some((error) => error.includes("Comment detected"))).toBe(true);
+			expect(errors.some((error) => error.includes("Comment detected"))).toBe(
+				true,
+			);
 		});
 		it("allows comments when noComments is false", () => {
 			const content = `const a = 1;
@@ -322,7 +331,9 @@ const b = 2;
 			const errors = checkFile(filePath, { noComments: false });
 
 			cleanupTempFile(filePath);
-			expect(errors.some((error) => error.includes("Comment detected"))).toBe(false);
+			expect(errors.some((error) => error.includes("Comment detected"))).toBe(
+				false,
+			);
 		});
 		it("detects JSDoc comments by default", () => {
 			const content = `/**
@@ -334,7 +345,9 @@ function test() {}
 			const errors = checkFile(filePath);
 
 			cleanupTempFile(filePath);
-			expect(errors.some((error) => error.includes("Comment detected"))).toBe(true);
+			expect(errors.some((error) => error.includes("Comment detected"))).toBe(
+				true,
+			);
 		});
 	});
 });
diff --git a/packages/iku/src/checker.ts b/packages/iku/src/checker.ts
index a69a232..f3e4a65 100644
--- a/packages/iku/src/checker.ts
+++ b/packages/iku/src/checker.ts
@@ -13,6 +13,7 @@ const defaultOptions: CheckerOptions = {
 type StatementCategory =
 	| "import"
 	| "variableDeclaration"
+	| "typeAlias"
 	| "if"
 	| "for"
 	| "while"
@@ -37,11 +38,19 @@ function getStatementCategory(node: typescript.Statement): StatementCategory {
 		return "variableDeclaration";
 	}
 
+	if (typescript.isTypeAliasDeclaration(node)) {
+		return "typeAlias";
+	}
+
 	if (typescript.isIfStatement(node)) {
 		return "if";
 	}
 
-	if (typescript.isForStatement(node) || typescript.isForInStatement(node) || typescript.isForOfStatement(node)) {
+	if (
+		typescript.isForStatement(node) ||
+		typescript.isForInStatement(node) ||
+		typescript.isForOfStatement(node)
+	) {
 		return "for";
 	}
 
@@ -69,7 +78,11 @@ function statementHasBlock(node: typescript.Statement): boolean {
 		return typescript.isBlock(node.thenStatement);
 	}
 
-	if (typescript.isForStatement(node) || typescript.isForInStatement(node) || typescript.isForOfStatement(node)) {
+	if (
+		typescript.isForStatement(node) ||
+		typescript.isForInStatement(node) ||
+		typescript.isForOfStatement(node)
+	) {
 		return typescript.isBlock(node.statement);
 	}
 
@@ -81,6 +94,10 @@ function statementHasBlock(node: typescript.Statement): boolean {
 		return typescript.isBlock(node.statement);
 	}
 
+	if (typescript.isTypeAliasDeclaration(node)) {
+		return typescript.isTypeLiteralNode(node.type);
+	}
+
 	return false;
 }
 
@@ -94,8 +111,10 @@ function getStatementsFromBlock(
 		const category = getStatementCategory(statement);
 		const startPosition = statement.getStart(sourceFile);
 		const endPosition = statement.getEnd();
-		const startLine = sourceFile.getLineAndCharacterOfPosition(startPosition).line + 1;
-		const endLine = sourceFile.getLineAndCharacterOfPosition(endPosition).line + 1;
+		const startLine =
+			sourceFile.getLineAndCharacterOfPosition(startPosition).line + 1;
+		const endLine =
+			sourceFile.getLineAndCharacterOfPosition(endPosition).line + 1;
 		const hasBlock = statementHasBlock(statement);
 
 		statements.push({ category, startLine, endLine, hasBlock });
@@ -113,7 +132,11 @@ function countBlankLinesBetween(
 	const lines = text.split("\n");
 	let blankCount = 0;
 
-	for (let lineIndex = previousEndLine; lineIndex < currentStartLine - 1; lineIndex++) {
+	for (
+		let lineIndex = previousEndLine;
+		lineIndex < currentStartLine - 1;
+		lineIndex++
+	) {
 		const line = lines[lineIndex];
 
 		if (line !== undefined && line.trim() === "") {
@@ -132,13 +155,22 @@ function hasCommentBetween(
 	const text = sourceFile.getFullText();
 	const lines = text.split("\n");
 
-	for (let lineIndex = previousEndLine; lineIndex < currentStartLine - 1; lineIndex++) {
+	for (
+		let lineIndex = previousEndLine;
+		lineIndex < currentStartLine - 1;
+		lineIndex++
+	) {
 		const line = lines[lineIndex];
 
 		if (line !== undefined) {
 			const trimmed = line.trim();
 
-			if (trimmed.startsWith("//") || trimmed.startsWith("/*") || trimmed.startsWith("*") || trimmed.endsWith("*/")) {
+			if (
+				trimmed.startsWith("//") ||
+				trimmed.startsWith("/*") ||
+				trimmed.startsWith("*") ||
+				trimmed.endsWith("*/")
+			) {
 				return true;
 			}
 		}
@@ -167,33 +199,50 @@ function checkStatementSpacing(
 			continue;
 		}
 
-		const blankLines = countBlankLinesBetween(previous.endLine, current.startLine, sourceFile);
+		const blankLines = countBlankLinesBetween(
+			previous.endLine,
+			current.startLine,
+			sourceFile,
+		);
 		const sameCategory = previous.category === current.category;
-		const hasComment = hasCommentBetween(previous.endLine, current.startLine, sourceFile);
+		const hasComment = hasCommentBetween(
+			previous.endLine,
+			current.startLine,
+			sourceFile,
+		);
 
 		if (previous.category === "import" && current.category === "import") {
 			if (blankLines > 0 && !(allowComments && hasComment)) {
-				errors.push(`${filePath}:${current.startLine}: Blank line between imports`);
+				errors.push(
+					`${filePath}:${current.startLine}: Blank line between imports`,
+				);
 			}
 
 			continue;
 		}
 
-		const bothHaveBlocks = previous.hasBlock && current.hasBlock;
+		const eitherHasBlock = previous.hasBlock || current.hasBlock;
 
-		if (sameCategory && !bothHaveBlocks && blankLines > 0 && !(allowComments && hasComment)) {
+		if (eitherHasBlock && blankLines === 0) {
 			errors.push(
-				`${filePath}:${current.startLine}: Unnecessary blank line between same statement types (${current.category})`,
+				`${filePath}:${current.startLine}: Missing blank line around scoped block`,
 			);
+
+			continue;
 		}
 
-		if (sameCategory && bothHaveBlocks && blankLines === 0) {
+		if (
+			sameCategory &&
+			!eitherHasBlock &&
+			blankLines > 0 &&
+			!(allowComments && hasComment)
+		) {
 			errors.push(
-				`${filePath}:${current.startLine}: Missing blank line between scoped blocks of same type (${current.category})`,
+				`${filePath}:${current.startLine}: Unnecessary blank line between same statement types (${current.category})`,
 			);
 		}
 
-		if (!sameCategory && blankLines === 0 && !hasComment) {
+		if (!sameCategory && !eitherHasBlock && blankLines === 0 && !hasComment) {
 			errors.push(
 				`${filePath}:${current.startLine}: Missing blank line between different statement types (${previous.category} -> ${current.category})`,
 			);
@@ -212,7 +261,12 @@ function visitBlocks(
 ): void {
 	if (typescript.isBlock(node)) {
 		const statements = getStatementsFromBlock(node, sourceFile);
-		const blockErrors = checkStatementSpacing(statements, sourceFile, filePath, allowComments);
+		const blockErrors = checkStatementSpacing(
+			statements,
+			sourceFile,
+			filePath,
+			allowComments,
+		);
 
 		errors.push(...blockErrors);
 	}
@@ -222,17 +276,27 @@ function visitBlocks(
 	});
 }
 
-function checkForComments(sourceFile: typescript.SourceFile, filePath: string): string[] {
+function checkForComments(
+	sourceFile: typescript.SourceFile,
+	filePath: string,
+): string[] {
 	const errors: string[] = [];
 	const text = sourceFile.getFullText();
 
 	function visit(node: typescript.Node): void {
-		const leadingComments = typescript.getLeadingCommentRanges(text, node.getFullStart());
-		const trailingComments = typescript.getTrailingCommentRanges(text, node.getEnd());
+		const leadingComments = typescript.getLeadingCommentRanges(
+			text,
+			node.getFullStart(),
+		);
+		const trailingComments = typescript.getTrailingCommentRanges(
+			text,
+			node.getEnd(),
+		);
 
 		if (leadingComments) {
 			for (const comment of leadingComments) {
-				const line = sourceFile.getLineAndCharacterOfPosition(comment.pos).line + 1;
+				const line =
+					sourceFile.getLineAndCharacterOfPosition(comment.pos).line + 1;
 
 				errors.push(`${filePath}:${line}: Comment detected`);
 			}
@@ -240,7 +304,8 @@ function checkForComments(sourceFile: typescript.SourceFile, filePath: string):
 
 		if (trailingComments) {
 			for (const comment of trailingComments) {
-				const line = sourceFile.getLineAndCharacterOfPosition(comment.pos).line + 1;
+				const line =
+					sourceFile.getLineAndCharacterOfPosition(comment.pos).line + 1;
 
 				errors.push(`${filePath}:${line}: Comment detected`);
 			}
@@ -256,7 +321,10 @@ function checkForComments(sourceFile: typescript.SourceFile, filePath: string):
 	return uniqueErrors;
 }
 
-export function checkFile(filePath: string, options: CheckerOptions = defaultOptions): string[] {
+export function checkFile(
+	filePath: string,
+	options: CheckerOptions = defaultOptions,
+): string[] {
 	const program = typescript.createProgram([filePath], {
 		target: typescript.ScriptTarget.ESNext,
 		module: typescript.ModuleKind.ESNext,
@@ -274,7 +342,12 @@ export function checkFile(filePath: string, options: CheckerOptions = defaultOpt
 	const allowComments = !options.noComments;
 	const errors: string[] = [];
 	const topLevelStatements = getStatementsFromBlock(sourceFile, sourceFile);
-	const topLevelErrors = checkStatementSpacing(topLevelStatements, sourceFile, filePath, allowComments);
+	const topLevelErrors = checkStatementSpacing(
+		topLevelStatements,
+		sourceFile,
+		filePath,
+		allowComments,
+	);
 
 	errors.push(...topLevelErrors);
 	visitBlocks(sourceFile, sourceFile, filePath, errors, allowComments);
@@ -296,10 +369,17 @@ export function walkDirectory(directory: string): string[] {
 		const stat = statSync(fullPath);
 
 		if (stat.isDirectory()) {
-			if (!entry.includes("node_modules") && !entry.includes("dist") && !entry.includes(".next")) {
+			if (
+				!entry.includes("node_modules") &&
+				!entry.includes("dist") &&
+				!entry.includes(".next")
+			) {
 				files.push(...walkDirectory(fullPath));
 			}
-		} else if ([".ts", ".tsx"].includes(extname(entry)) && !entry.endsWith(".d.ts")) {
+		} else if (
+			[".ts", ".tsx"].includes(extname(entry)) &&
+			!entry.endsWith(".d.ts")
+		) {
 			files.push(fullPath);
 		}
 	}
diff --git a/packages/iku/src/cli.ts b/packages/iku/src/cli.ts
index 8ea07a4..aea9350 100644
--- a/packages/iku/src/cli.ts
+++ b/packages/iku/src/cli.ts
@@ -21,7 +21,10 @@ function findMonorepoRoot(startDirectory: string): string | null {
 	return null;
 }
 
-function parseArguments(arguments_: string[]): { directory?: string; options: CheckerOptions } {
+function parseArguments(arguments_: string[]): {
+	directory?: string;
+	options: CheckerOptions;
+} {
 	const options: CheckerOptions = {
 		noComments: true,
 	};
diff --git a/packages/iku/src/index.ts b/packages/iku/src/index.ts
index d3d29ae..d175fb5 100644
--- a/packages/iku/src/index.ts
+++ b/packages/iku/src/index.ts
@@ -1 +1,6 @@
-export { checkFile, walkDirectory, checkDirectory, type CheckerOptions } from "./checker.js";
+export {
+	checkFile,
+	walkDirectory,
+	checkDirectory,
+	type CheckerOptions,
+} from "./checker.js";