ci: report semantic release in PR

.github/workflows/library.yml

@@ -41,13 +41,71 @@ jobs:
             - name: Install dependencies
               uses: bahmutov/npm-install@v1
             - name: Preview release
+              id: semantic-release
               run: |
                   # locally checkout to the base branch (destination) and merge the head branch (source)
                   git checkout -b ${{ github.base_ref }} pull/${{ github.event.number }}/merge
-                  unset GITHUB_ACTIONS; npx semantic-release --no-ci --dry-run
+                  unset GITHUB_ACTIONS; npx semantic-release --no-ci --dry-run > output.txt
+                  OUTPUT=$(cat output.txt | base64 -w 0)
+                  echo "::set-output name=releaseNote::$OUTPUT"
               env:
                   GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
                   NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
+            - name: Report semantic versioning
+              uses: actions/github-script@v3
+              if: ${{ steps.semantic-release.outputs.releaseNote != '' }}
+              with:
+                  github-token: ${{ secrets.GITHUB_TOKEN }}
+                  script: |
+                      // build release note
+                      const semanticReleaseOutput = Buffer.from('${{ steps.semantic-release.outputs.releaseNote }}', 'base64').toString('utf8');
+                      const semanticReleaseLogMatch = /^[[0-9:\sAMPM]+\]\s\[semantic-release\].*$/;
+                      const lines = semanticReleaseOutput.split('\n');
+                      const lastSemanticReleaseLogIndex = [...lines]
+                          .reverse()
+                          .findIndex((line) => line.match(semanticReleaseLogMatch));
+
+                      const releaseNoteIndex = lines.length - lastSemanticReleaseLogIndex;
+                      const releaseNote = lines.slice(releaseNoteIndex);
+
+                      let res = releaseNote.join('\n');
+                      if (!releaseNote.length || !res) {
+                          res = '### No release note would be generated.';
+                      }
+
+                      const SEMANTIC_RELEASE_BODY_HEADER = '## 📝 Semantic Release Report';
+                      const body = [SEMANTIC_RELEASE_BODY_HEADER, res].join('\n');
+
+                      // get last comment
+                      const comments = await github.issues.listComments({
+                          issue_number: context.issue.number,
+                          owner: context.repo.owner,
+                          repo: context.repo.repo
+                      });
+
+                      // find comments to delete
+                      const commentsToDelete = comments.data.filter((comment) =>
+                          comment.body.startsWith(SEMANTIC_RELEASE_BODY_HEADER)
+                      );
+
+                      // delete comments
+                      const prms = commentsToDelete.map((comment) =>
+                          github.issues.deleteComment({
+                              comment_id: comment.id,
+                              owner: context.repo.owner,
+                              repo: context.repo.repo
+                          })
+                      );
+
+                      await Promise.all(prms);
+
+                      // create new comment for release note
+                      github.issues.createComment({
+                          issue_number: context.issue.number,
+                          owner: context.repo.owner,
+                          repo: context.repo.repo,
+                          body
+                      });
 
     release:
         if: github.ref == 'refs/heads/main'