fix: raise error when no default export found in config file (#96)

Co-authored-by: Eric Cornelissen <ericornelissen@gmail.com>

bin/cli.js

@@ -86,6 +86,9 @@ process.on("exit", () => {
             } else {
                 configObj = {};
             }
+        } else if (configObj === undefined) {
+            logger.error("Default export missing from configuration file (use `export default {...}` or `module.exports = {...}`");
+            process.exit(EXIT_CODES.configuration);
         }
     } catch (e) {
         logger.error(`Failed to parse config: ${e.stack}`);

test/cli.spec.js

@@ -83,6 +83,14 @@ describe("Configuration files", function() {
         expect(exitCode).toBe(4);
     });
 
+    it("should fail with a configuration file without default export", async function(){
+        const { failed, exitCode } = await execCliWith(
+            ["--config", "./test/projects/with-config-no-default-export/.svglintrc.js"]
+        );
+        expect(failed).toBeTruthy();
+        expect(exitCode).toBe(4);
+    });
+
     it("should succeed passing an existent file path to --config", async function() {
         const { failed } = await execCliWith(
             [VALID_SVG, "--config", "test/projects/esm/foo/custom-svglint-config.js"]

test/projects/with-config-no-default-export/.svglintrc.js

@@ -0,0 +1,11 @@
+export const config = {
+    rules: {
+        attr: {
+            "rule::selector": "path",
+            "d": true,
+        },
+        elm: {
+            "g": true,
+        }
+    }
+};