added prerelease check

__tests__/action.test.ts

@@ -0,0 +1,31 @@
+import * as core from '@actions/core';
+import {context} from '@actions/github';
+import {isPrelease} from '../src/action';
+
+describe("publish_latest tests", () => {
+    test("not published when false", () => {
+        process.env.INPUT_PUBLISH_LATEST = 'false';
+        expect(core.getInput('publish_latest')).toBe('false')
+    });
+
+    test("published when true", () => {
+        process.env.INPUT_PUBLISH_LATEST = "true";
+        expect(core.getInput('publish_latest')).toBe('true')
+    });
+});
+
+describe("release tests", () => {
+    test("Will return true if Pre-release detected", () => {
+        context.payload = {action: 'published', release: {
+            "prerelease": true
+        }}
+        expect(isPrelease()).toBe(true);
+    });
+
+    test("Will return false if not Pre-release", () => {
+        context.payload = {action: 'published', release: {
+            "prerelease": false
+        }}
+        expect(isPrelease()).toBe(false);
+    });
+});

src/action.ts

@@ -7,11 +7,23 @@ import { TaggedRelease } from ".";
 /**
  * Checks if the event that triggered this action was a release
  * See: https://developer.github.com/v3/activity/events/types/#releaseevent
+ *
+ * @returns {boolean}
  */
 function isRelease(): boolean {
     return context.payload.action === "published" && valid(context.payload.release?.tag_name) !== null;
 }
 
+/**
+ * Check if the event that triggered this actions was as a result
+ * of a prerelease or not
+ *
+ * @returns {boolean}
+ */
+export function isPrelease(): boolean {
+    return context.payload.action === "published" && context.payload.release?.prerelease === true;
+}
+
 /**
  * Creates the tags required and optionally a 'latest' tag
  *
@@ -79,6 +91,12 @@ async function run() {
             return;
         }
 
+        if (isPrelease()) {
+            core.info("Pre-release detected. Nothing to be done.");
+            core.info("See https://github.com/Actions-R-Us/actions-tagger/issues/23");
+            return;
+        }
+
         if (process.env.GITHUB_TOKEN) {
             const { tag, latest } = await createTagRefs();
             core.setOutput("tag", tag);