feat(eslint): downgrade unused variables to warning

src/public/app/services/eslint.spec.ts

@@ -26,4 +26,23 @@ describe("Linter", () => {
         `);
         expect(result.length).toBe(0);
     });
+
+    it("reports unused functions as warnings", async () => {
+        const result = await lint(trimIndentation`
+            function hello() { }
+            function world() { }
+
+            console.log("Hello world");
+        `);
+        expect(result).toMatchObject([
+            {
+                message: "'hello' is defined but never used.",
+                severity: 1
+            },
+            {
+                message: "'world' is defined but never used.",
+                severity: 1
+            }
+        ]);
+    });
 });

src/public/app/services/eslint.ts

@@ -14,9 +14,11 @@ export async function lint(code: string) {
                 globals: {
                     ...globals.browser,
                     api: "readonly"
-                }
                 },
-            rules: { }
+            },
+            rules: {
+                "no-unused-vars": [ "warn", { vars: "local", args: "after-used" }]
+            }
         }
     ]);