Fixes #6 Add support for updating releases

src/Action.ts

@@ -1,6 +1,8 @@
 import { Inputs } from "./Inputs";
 import { Releases } from "./Releases";
 import { ArtifactUploader } from "./ArtifactUploader";
+import { ErrorMessage } from "./ErrorMessage";
+import { Response, ReposCreateReleaseResponse } from "@octokit/rest";
 
 export class Action {
     private inputs: Inputs
@@ -14,7 +16,28 @@ export class Action {
     }
 
     async perform() {
-        const createResult = await this.releases.create(
+        const uploadUrl = await this.createOrUpdateRelease()
+
+        const artifacts = this.inputs.artifacts
+        if (artifacts.length > 0) {
+            await this.uploader.uploadArtifacts(artifacts, uploadUrl)
+        }
+    }
+
+    private async createOrUpdateRelease(): Promise<string> {
+        try {
+            return await this.createRelease()
+        } catch (error) {
+            if (this.releaseAlreadyExisted(error) && this.inputs.allowUpdates) {
+                return this.updateRelease()
+            } else {
+                throw error
+            }
+        }
+    }
+
+    private async createRelease(): Promise<string> {
+        const response = await this.releases.create(
             this.inputs.tag,
             this.inputs.body,
             this.inputs.commit,
@@ -22,12 +45,27 @@ export class Action {
             this.inputs.name
         )
 
-        const artifacts = this.inputs.artifacts
-        if (artifacts.length > 0) {
-            await this.uploader.uploadArtifacts(
-                artifacts,
-                createResult.data.upload_url
-            )
-        }
+        return response.data.upload_url
+    }
+
+    private releaseAlreadyExisted(error: any): boolean {
+        const errorMessage = new ErrorMessage(error)
+        return errorMessage.hasErrorWithCode('already_exists')
+    }
+
+    private async updateRelease(): Promise<string> {
+        const getResponse = await this.releases.getByTag(this.inputs.tag)
+        const id = getResponse.data.id
+
+        const response = await this.releases.update(
+            id,
+            this.inputs.tag,
+            this.inputs.body,
+            this.inputs.commit,
+            this.inputs.draft,
+            this.inputs.name
+        )
+
+        return response.data.upload_url
     }
 }