1 files changed, 55 insertions, 0 deletions
diff --git a/packages/monorepo-scripts/src/utils/changelog_utils.ts b/packages/monorepo-scripts/src/utils/changelog_utils.ts
new file mode 100644
index 000000000..edfe65a80
--- /dev/null
+++ b/packages/monorepo-scripts/src/utils/changelog_utils.ts
@@ -0,0 +1,55 @@
+import * as _ from 'lodash';
+import * as moment from 'moment';
+
+import { Change, Changelog, VersionChangelog } from '../types';
+
+const CHANGELOG_MD_HEADER = `
+<!--
+This file is auto-generated using the monorepo-scripts package. Don't edit directly.
+Edit the package's CHANGELOG.json file only.
+-->
+
+CHANGELOG
+`;
+
+export const changelogUtils = {
+    getChangelogMdTitle(versionChangelog: VersionChangelog): string {
+        if (_.isUndefined(versionChangelog.timestamp)) {
+            throw new Error(
+                'All CHANGELOG.json entries must be updated to include a timestamp before generating their MD version',
+            );
+        }
+        const date = moment(`${versionChangelog.timestamp}`, 'X').format('MMMM D, YYYY');
+        const title = `\n## v${versionChangelog.version} - _${date}_\n\n`;
+        return title;
+    },
+    getChangelogMdChange(change: Change): string {
+        let line = `    * ${change.note}`;
+        if (!_.isUndefined(change.pr)) {
+            line += ` (#${change.pr})`;
+        }
+        return line;
+    },
+    generateChangelogMd(changelog: Changelog): string {
+        let changelogMd = CHANGELOG_MD_HEADER;
+        _.each(changelog, versionChangelog => {
+            const title = changelogUtils.getChangelogMdTitle(versionChangelog);
+            changelogMd += title;
+            const changelogVersionLines = _.map(
+                versionChangelog.changes,
+                changelogUtils.getChangelogMdChange.bind(changelogUtils),
+            );
+            changelogMd += `${_.join(changelogVersionLines, '\n')}`;
+        });
+
+        return changelogMd;
+    },
+    shouldAddNewChangelogEntry(currentVersion: string, changelog: Changelog): boolean {
+        if (_.isEmpty(changelog)) {
+            return true;
+        }
+        const lastEntry = changelog[0];
+        const isLastEntryCurrentVersion = lastEntry.version === currentVersion;
+        return isLastEntryCurrentVersion;
+    },
+};