@truenine/eslint9-config/dist/rules/single-line/control.cjs

ESLint 9 configuration package for Compose Client projects with TypeScript, Vue, and modern JavaScript support

//#region src/rules/single-line/control.ts
const MAX_LINE_LENGTH = 160;
/**
* ESLint rule: prefer-single-line-control
* Prefer single-line switch cases, for loops, while loops, and try-catch when possible.
*/
const rule = {
	meta: {
		type: "layout",
		docs: {
			description: "Prefer single-line switch cases, for loops, while loops, and try-catch when possible",
			recommended: false
		},
		fixable: "code",
		schema: [],
		messages: {
			preferSingleLineCase: "Switch case with simple statement should be single-line format",
			preferSingleLineFor: "For loop with simple body should be single-line format",
			preferSingleLineWhile: "While loop with simple body should be single-line format",
			preferSingleLineTry: "Try-catch with simple bodies should be single-line format",
			preferBraceCatch: "} catch should be on the same line",
			preferBraceFinally: "} finally should be on the same line"
		}
	},
	create(context) {
		const { sourceCode } = context;
		function getSingleStatement(node) {
			if (!node) return null;
			if (node.type !== "BlockStatement") return node;
			const { body } = node;
			return Array.isArray(body) && body.length === 1 ? body[0] : null;
		}
		function hasComments(node) {
			return sourceCode.getCommentsInside(node).length > 0;
		}
		function isSimpleStatement(stmt) {
			if (!stmt) return false;
			return new Set([
				"ExpressionStatement",
				"ReturnStatement",
				"ThrowStatement",
				"BreakStatement",
				"ContinueStatement"
			]).has(stmt.type);
		}
		function isNodeSingleLine(node) {
			return node.loc?.start.line === node.loc?.end.line;
		}
		function normalizeText(text) {
			return text.split("\n").map((l) => l.trim()).join(" ").replaceAll(/\s+/g, " ").trim();
		}
		function ensureSemicolon(text) {
			return text.trimEnd().endsWith(";") ? text.trimEnd() : `${text.trimEnd()};`;
		}
		function extractCaseStatements(consequent) {
			if (!Array.isArray(consequent) || consequent.length === 0) return {
				mainStmt: null,
				hasBreak: false
			};
			if (consequent.length === 1) {
				if (isSimpleStatement(consequent[0])) return {
					mainStmt: consequent[0],
					hasBreak: false
				};
			}
			if (consequent.length === 2 && isSimpleStatement(consequent[0]) && consequent[1].type === "BreakStatement") return {
				mainStmt: consequent[0],
				hasBreak: true
			};
			if (consequent.length !== 1 || consequent[0].type !== "BlockStatement") return {
				mainStmt: null,
				hasBreak: false
			};
			const { body } = consequent[0];
			if (!Array.isArray(body) || body.length === 0 || body.length > 2) return {
				mainStmt: null,
				hasBreak: false
			};
			const hasBreak = body.length === 2 && body[1].type === "BreakStatement";
			return (body.length === 1 || hasBreak) && isSimpleStatement(body[0]) ? {
				mainStmt: body[0],
				hasBreak
			} : {
				mainStmt: null,
				hasBreak: false
			};
		}
		function canCaseBeSimplified(caseNode) {
			const { consequent, test } = caseNode;
			const { mainStmt, hasBreak } = extractCaseStatements(consequent);
			if (!mainStmt || !isNodeSingleLine(mainStmt) || hasComments(caseNode)) return false;
			return `case ${test != null ? normalizeText(sourceCode.getText(test)) : "default"}: ${ensureSemicolon(sourceCode.getText(mainStmt))}${hasBreak ? " break" : ""}`.length < MAX_LINE_LENGTH;
		}
		function canLoopBeSimplified(loopNode) {
			const { body } = loopNode;
			if (body?.type !== "BlockStatement" || hasComments(body)) return false;
			const stmt = getSingleStatement(body);
			if (!stmt || !isSimpleStatement(stmt) || !isNodeSingleLine(stmt)) return false;
			return `${normalizeText(sourceCode.getText(loopNode).slice(0, (body.range?.[0] ?? 0) - (loopNode.range?.[0] ?? 0)))} ${sourceCode.getText(stmt)}`.length < MAX_LINE_LENGTH;
		}
		function isLoopAlreadySingleLine(l) {
			return l.body == null || l.body.type === "BlockStatement" ? false : l.loc?.start.line === l.body.loc?.end.line;
		}
		const loopVisitor = (messageId) => (node) => {
			const l = node;
			if (isLoopAlreadySingleLine(l) || !canLoopBeSimplified(l)) return;
			context.report({
				node,
				messageId,
				fix: (fixer) => {
					const stmt = getSingleStatement(l.body);
					if (node.type === "WhileStatement") return fixer.replaceText(node, `while (${normalizeText(sourceCode.getText(node.test))}) ${sourceCode.getText(stmt).trimEnd()}`);
					const h = normalizeText(sourceCode.getText(node).slice(0, (l.body.range?.[0] ?? 0) - (node.range?.[0] ?? 0)));
					return fixer.replaceText(node, `${h} ${sourceCode.getText(stmt).trimEnd()}`);
				}
			});
		};
		return {
			SwitchStatement(node) {
				const { cases } = node;
				cases?.forEach((c) => {
					if (c.loc?.start.line !== c.loc?.end.line && canCaseBeSimplified(c)) context.report({
						node: c,
						messageId: "preferSingleLineCase",
						fix: (fixer) => {
							const { mainStmt, hasBreak } = extractCaseStatements(c.consequent);
							const tText = c.test ? `case ${normalizeText(sourceCode.getText(c.test))}:` : "default:";
							return fixer.replaceText(c, `${tText} ${ensureSemicolon(sourceCode.getText(mainStmt))}${hasBreak ? " break" : ""}`);
						}
					});
				});
			},
			ForStatement: loopVisitor("preferSingleLineFor"),
			ForInStatement: loopVisitor("preferSingleLineFor"),
			ForOfStatement: loopVisitor("preferSingleLineFor"),
			WhileStatement: loopVisitor("preferSingleLineWhile"),
			DoWhileStatement() {}
		};
	}
};

//#endregion
module.exports = rule;
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