Make the catch-error-name rule fixable in most cases (#209)

Fixes #189

Author: futpib

docs/rules/catch-error-name.md

@@ -4,6 +4,8 @@ Applies to both `try/catch` clauses and `promise.catch(...)` handlers.
 
 The desired name is configurable, but defaults to `error`.
 
+This rule is fixable unless the reported code was destructuring an error.
+
 
 ## Fail
 

rules/catch-error-name.js

@@ -58,10 +58,29 @@ const create = context => {
 		const value = stack.pop();
 
 		if (value !== true && !caughtErrorsIgnorePattern.test(node.name)) {
-			context.report({
+			const expectedName = value || name;
+			const problem = {
 				node,
-				message: `The catch parameter should be named \`${value || name}\`.`
-			});
+				message: `The catch parameter should be named \`${expectedName}\`.`
+			};
+
+			if (node.type === 'Identifier') {
+				problem.fix = fixer => {
+					const fixings = [fixer.replaceText(node, expectedName)];
+
+					const scope = context.getScope();
+					const variable = scope.set.get(node.name);
+					if (variable) {
+						for (const reference of variable.references) {
+							fixings.push(fixer.replaceText(reference.identifier, expectedName));
+						}
+					}
+
+					return fixings;
+				};
+			}
+
+			context.report(problem);
 		}
 	}
 
@@ -123,6 +142,7 @@ module.exports = {
 		docs: {
 			url: getDocsUrl(__filename)
 		},
+		fixable: 'code',
 		schema
 	}
 };

test/catch-error-name.js

@@ -8,9 +8,10 @@ const ruleTester = avaRuleTester(test, {
 	}
 });
 
-function testCase(code, name, error) {
+function testCase(code, name, error, output) {
 	return {
 		code,
+		output: output || code,
 		options: name ? [{name}] : [],
 		errors: error ? [{ruleId: 'catch-error-name'}] : []
 	};
@@ -130,18 +131,19 @@ ruleTester.run('catch-error-name', rule, {
 		// 	}
 		// `),
 	],
+
 	invalid: [
-		testCase('try {} catch (err) {}', null, true),
-		testCase('try {} catch (error) {}', 'err', true),
+		testCase('try {} catch (err) {}', null, true, 'try {} catch (error) {}'),
+		testCase('try {} catch (error) {}', 'err', true, 'try {} catch (err) {}'),
 		testCase('try {} catch ({message}) {}', null, true),
-		testCase('try {} catch (outerError) {}', null, true),
-		testCase('try {} catch (innerError) {}', null, true),
-		testCase('obj.catch(err => {})', null, true),
-		testCase('obj.catch(error => {})', 'err', true),
+		testCase('try {} catch (outerError) {}', null, true, 'try {} catch (error) {}'),
+		testCase('try {} catch (innerError) {}', null, true, 'try {} catch (error) {}'),
+		testCase('obj.catch(err => {})', null, true, 'obj.catch(error => {})'),
+		testCase('obj.catch(error => {})', 'err', true, 'obj.catch(err => {})'),
 		testCase('obj.catch(({message}) => {})', null, true),
-		testCase('obj.catch(function (err) {})', null, true),
+		testCase('obj.catch(function (err) {})', null, true, 'obj.catch(function (error) {})'),
 		testCase('obj.catch(function ({message}) {})', null, true),
-		testCase('obj.catch(function (error) {})', 'err', true),
+		testCase('obj.catch(function (error) {})', 'err', true, 'obj.catch(function (err) {})'),
 		// Failing tests for #107
 		// testCase(`
 		// 	foo.then(() => {
@@ -163,6 +165,15 @@ ruleTester.run('catch-error-name', rule, {
 					}
 				}
 			`,
+			output: `
+				const handleError = error => {
+					try {
+						doSomething();
+					} catch (error2) {
+						console.log(error2);
+					}
+				}
+			`,
 			errors: [
 				{
 					ruleId: 'catch-error-name',
@@ -182,6 +193,17 @@ ruleTester.run('catch-error-name', rule, {
 					}
 				}
 			`,
+			output: `
+				const handleError = error => {
+					const error9 = new Error('foo bar');
+
+					try {
+						doSomething();
+					} catch (error2) {
+						console.log(error2);
+					}
+				}
+			`,
 			errors: [
 				{
 					ruleId: 'catch-error-name',
@@ -197,6 +219,13 @@ ruleTester.run('catch-error-name', rule, {
 					obj.catch(foo => { });
 				}
 			`,
+			output: `
+				const handleError = error => {
+					const error2 = new Error('foo bar');
+
+					obj.catch(error3 => { });
+				}
+			`,
 			errors: [
 				{
 					ruleId: 'catch-error-name',
@@ -212,6 +241,13 @@ ruleTester.run('catch-error-name', rule, {
 					obj.catch(foo => { });
 				}
 			`,
+			output: `
+				const handleError = error => {
+					const error2 = new Error('foo bar');
+
+					obj.catch(error3 => { });
+				}
+			`,
 			errors: [
 				{
 					ruleId: 'catch-error-name',
@@ -229,13 +265,18 @@ ruleTester.run('catch-error-name', rule, {
 				obj.catch(err => {});
 				obj.catch(err => {});
 			`,
+			output: `
+				obj.catch(error => {});
+				obj.catch(error => {});
+			`,
 			errors: [
 				{ruleId: 'catch-error-name'},
 				{ruleId: 'catch-error-name'}
 			]
 		},
 		{
 			code: 'try {} catch (_error) {}',
+			output: 'try {} catch (error) {}',
 			errors: [
 				{
 					ruleId: 'catch-error-name',