Action generates PR comments for preview command

Author: minkimcello

packages/action/dist/index.js

@@ -123,13 +123,72 @@ export function* run(): Generator<any, any, any> {
         });
 
         if (covectored) {
-          let packagesPublished = Object.keys(covectored).reduce((pub, pkg) => {
-            if (!covectored[pkg].published) {
-              return pub;
+          let packagesPublished = Object.entries(covectored).reduce((pub, pkg) => {
+            //@ts-ignore
+            if(pkg[1].published){
+              //@ts-ignore
+              let { name: pkgName, version: pkgVersion } = pkg[1].pkg.pkgFile.pkg
+              return pub.concat(`${pkgName}@${pkgVersion}`);
+            }
+          }, []);
+
+          if (token && github.context.payload.pull_request) {
+            const octokit = github.getOctokit(token);
+            const { 
+              pull_request: { 
+                number: issue_number,
+              }, 
+              repository: {
+                name: repo,
+                owner: {
+                  login: owner
+                }
+              },
+              after
+            } = github.context.payload;
+
+            const { data } = yield octokit.rest.issues.listComments({
+              owner,
+              repo,
+              issue_number,
+            });
+
+            const covectorComments = data.filter(comment => comment.body.includes('<!-- covector comment -->'));
+
+            let prComment = () => {
+              let commentHead = '';
+              let commentBody = '';
+              if (packagesPublished.length) {
+                commentHead = `The following preview packages have been published by Covector:`
+                commentBody = packagesPublished.reduce((result, publishedPackage) => {
+                  return `${result}- \`${publishedPackage}\`\n`;
+                }, '')
+              } else {
+                commentHead = "Covector did not publish any preview packages."
+              }
+              const commentFoot = `<p align="right">${after.slice(0, 7)}</p>`;
+              return `${commentHead}\n${commentBody}\n${commentFoot}\n<!-- covector comment -->`;
+            };
+
+            if (covectorComments.length !== 1) {
+              yield octokit.rest.issues.createComment({
+                owner,
+                repo,
+                issue_number,
+                body: prComment(),
+              });
             } else {
-              return `${pub}${pkg}`;
+              yield octokit.rest.issues.updateComment({
+                owner,
+                repo,
+                comment_id: covectorComments[0].id,
+                body: prComment(),
+              });
             }
-          }, "");
+          } else {
+            throw new Error(`Github token argument in preview workflow is missing but it is required in order to generate comments on pull requests.`);
+          }
+
           core.setOutput("packagesPublished", packagesPublished);
           for (let pkg of Object.keys(covectored)) {
             if (covectored[pkg].command !== false) successfulPublish = true;