Add caughtErrorsIgnorePattern option to catch-error-name rule (#137)

Author: evilebottnawi

docs/rules/catch-error-name.md

@@ -75,8 +75,39 @@ somePromise.catch(_ => {
 
 ## Options
 
+### name
+
 You can set the `name` option like this:
 
 ```js
 "unicorn/catch-error-name": ["error", {"name": "err"}]
 ```
+
+### caughtErrorsIgnorePattern
+
+```js
+"unicorn/catch-error-name": ["error", {"caughtErrorsIgnorePattern": "^_$"}]
+```
+
+The `caughtErrorsIgnorePattern` option specifies exceptions not to check for usage: catch arguments whose names match a regexp pattern.
+For example, variables whose names is a string `_`. Default is `^_$`.
+
+## Fail
+
+```js
+try {
+	doSomething();
+} catch (skipErr) {
+	// …
+}
+```
+
+## Pass
+
+```js
+try {
+	doSomething();
+} catch (_) {
+	// …
+}
+```

rules/catch-error-name.js

@@ -37,8 +37,9 @@ function indexifyName(name, scope) {
 }
 
 const create = context => {
-	const opts = context.options[0];
-	const name = (opts && opts.name) || 'err';
+	const opts = Object.assign({}, {name: 'err'}, context.options[0]);
+	const name = opts.name;
+	const caughtErrorsIgnorePattern = new RegExp(opts.caughtErrorsIgnorePattern || '^_$');
 	const stack = [];
 
 	function push(value) {
@@ -52,6 +53,10 @@ const create = context => {
 	function popAndReport(node) {
 		const value = stack.pop();
 
+		if (node && caughtErrorsIgnorePattern.test(node.name)) {
+			return;
+		}
+
 		if (value !== true) {
 			context.report({
 				node,
@@ -99,6 +104,9 @@ const schema = [{
 	properties: {
 		name: {
 			type: 'string'
+		},
+		caughtErrorsIgnorePattern: {
+			type: 'string'
 		}
 	}
 }];

test/catch-error-name.js

@@ -95,25 +95,45 @@ ruleTester.run('catch-error-name', rule, {
 		testCase('obj.catch(function (error) {})', 'error'),
 		testCase('obj.catch(function (outerError) { return obj2.catch(function (innerError) {}) })'),
 		testCase('obj.catch()'),
+		testCase('obj.catch(_ => { console.log(_); })'),
+		testCase('obj.catch(function (_) { console.log(_); })'),
 		testCase('foo(function (err) {})'),
 		testCase('foo().then(function (err) {})'),
-		testCase('foo().catch(function (err) {})')
+		testCase('foo().catch(function (err) {})'),
+		testCase('try {} catch (_) {}'),
+		testCase('try {} catch (_) { try {} catch (_) {} }'),
+		testCase('try {} catch (_) { console.log(_); }'),
+		testCase(`
+				const handleError = error => {
+					try {
+						doSomething();
+					} catch (_) {
+						console.log(_);
+					}
+				}
+		`),
+		testCase('obj.catch(_ => {})'),
+		{
+			code: 'try {} catch (skipErr) {}',
+			options: [
+				{
+					caughtErrorsIgnorePattern: '^skip'
+				}
+			]
+		}
 	],
 	invalid: [
 		testCase('try {} catch (error) {}', null, true),
 		testCase('try {} catch (err) {}', 'error', true),
 		testCase('try {} catch ({message}) {}', null, true),
-		testCase('try {} catch (_) { console.log(_); }', null, true),
 		testCase('try {} catch (outerError) {}', null, true),
 		testCase('try {} catch (innerError) {}', null, true),
 		testCase('obj.catch(error => {})', null, true),
 		testCase('obj.catch(err => {})', 'error', true),
 		testCase('obj.catch(({message}) => {})', null, true),
-		testCase('obj.catch(_ => { console.log(_); })', null, true),
 		testCase('obj.catch(function (error) {})', null, true),
 		testCase('obj.catch(function ({message}) {})', null, true),
 		testCase('obj.catch(function (err) {})', 'error', true),
-		testCase('obj.catch(function (_) { console.log(_); })', null, true),
 		// Failing tests for #107
 		// testCase(`
 		// 	foo.then(() => {
@@ -205,6 +225,20 @@ ruleTester.run('catch-error-name', rule, {
 				{ruleId: 'catch-error-name'},
 				{ruleId: 'catch-error-name'}
 			]
+		},
+		{
+			code: 'try {} catch (_err) {}',
+			errors: [
+				{
+					ruleId: 'catch-error-name',
+					message: 'The catch parameter should be named `err`.'
+				}
+			],
+			options: [
+				{
+					caughtErrorsIgnorePattern: '^skip'
+				}
+			]
 		}
 	]
 });