feat: improve label matching by making it case-insensitive (#76)

Fixes #75

README.md

@@ -21,6 +21,9 @@ This action calls the GitHub API to fetch labels for a PR rather than reading `e
 
 If successful, any matching labels will be output in `outputs.labels` as a comma separated string.
 
+> [!TIP]
+> Label matching is **case-insensitive**.
+
 ## Examples
 
 ### Complete example

index.js

@@ -86,11 +86,12 @@ async function action() {
     if (labelsAreRegex) {
       intersection = appliedLabels.filter((appliedLabel) =>
         providedLabels.some((providedLabel) =>
-          new RegExp(providedLabel).test(appliedLabel)
+          new RegExp(providedLabel, 'i').test(appliedLabel)
         )
       );
     } else {
-      intersection = providedLabels.filter((x) => appliedLabels.includes(x));
+      const lowerCasedAppliedLabels = appliedLabels.map((label) => label.toLowerCase());
+      intersection = providedLabels.filter((x) => lowerCasedAppliedLabels.includes(x.toLowerCase()));
     }
 
     // Is there an error?

index.test.js

@@ -446,6 +446,36 @@ describe("Required Labels", () => {
       expect(core.setOutput).toBeCalledWith("status", "success");
       expect(core.setOutput).toBeCalledWith("labels", "bug");
     });
+
+    it("is case insensitive when matching INPUT_LABELS", async () => {
+      restoreTest = mockPr({
+        INPUT_LABELS: "Do Not Merge",
+        INPUT_MODE: "exactly",
+        INPUT_COUNT: "1",
+      });
+      mockLabels(["DO NOT MERGE"]);
+
+      await action();
+      expect(core.setOutput).toBeCalledTimes(2);
+      expect(core.setOutput).toBeCalledWith("status", "success");
+      expect(core.setOutput).toBeCalledWith("labels", "Do Not Merge");
+    });
+
+    it("is case insensitive when matching INPUT_LABELS using regex", async () => {
+      restoreTest = mockPr({
+        INPUT_LABELS: "needs .*",
+        INPUT_MODE: "exactly",
+        INPUT_COUNT: "2",
+        INPUT_USE_REGEX: "true",
+      });
+      mockLabels(["Needs Code Review", "Needs QA Review", "Do Not Merge"]);
+
+      await action();
+
+      expect(core.setOutput).toBeCalledTimes(2);
+      expect(core.setOutput).toBeCalledWith("status", "success");
+      expect(core.setOutput).toBeCalledWith("labels", "Needs Code Review,Needs QA Review");
+    });
   });
 
   describe("configurable exit code", () => {