Fix custom-error-definition to support constructors without a body (#…

…442)

package.json

@@ -52,6 +52,7 @@
 	},
 	"devDependencies": {
 		"@lubien/fixture-beta-package": "^1.0.0-beta.1",
+		"@typescript-eslint/parser": "^2.9.0",
 		"ava": "^2.4.0",
 		"babel-eslint": "^10.0.3",
 		"chalk": "^2.4.2",
@@ -66,6 +67,7 @@
 		"outdent": "^0.7.0",
 		"pify": "^4.0.1",
 		"tempy": "^0.3.0",
+		"typescript": "^3.7.2",
 		"xo": "^0.25.3"
 	},
 	"peerDependencies": {

rules/custom-error-definition.js

@@ -80,6 +80,12 @@ const customErrorDefinition = (context, node) => {
 	}
 
 	const constructorBodyNode = constructor.value.body;
+
+	// Verify the constructor has a body (TypeScript)
+	if (!constructorBodyNode) {
+		return;
+	}
+
 	const constructorBody = constructorBodyNode.body;
 
 	const superExpression = constructorBody.find(isSuperExpression);

test/custom-error-definition.js

@@ -12,6 +12,10 @@ const ruleTester = avaRuleTester(test, {
 	}
 });
 
+const typescriptRuleTester = avaRuleTester(test, {
+	parser: require.resolve('@typescript-eslint/parser')
+});
+
 const invalidClassNameError = {ruleId: 'custom-error-definition', message: 'Invalid class name, use `FooError`.'};
 const constructorError = {ruleId: 'custom-error-definition', message: 'Add a constructor to your error.'};
 const noSuperCallError = {ruleId: 'custom-error-definition', message: 'Missing call to `super()` in constructor.'};
@@ -433,3 +437,14 @@ ruleTester.run('custom-error-definition', rule, {
 		}
 	]
 });
+
+typescriptRuleTester.run('custom-error-definition', rule, {
+	valid: [
+		outdent`
+			class CustomError extends Error {
+				constructor(type: string, text: string, reply?: any);
+			}
+		`
+	],
+	invalid: []
+});