feat: add utility to show experiment invitation notices (#28120)

packages/gatsby/src/utils/show-experiment-notice.ts

@@ -0,0 +1,37 @@
+import { getConfigStore } from "gatsby-core-utils"
+import reporter from "gatsby-cli/lib/reporter"
+
+type CancelExperimentNoticeCallback = () => void
+
+export type CancelExperimentNoticeCallbackOrUndefined =
+  | CancelExperimentNoticeCallback
+  | undefined
+
+const ONE_DAY = 24 * 60 * 60 * 1000
+
+export function showExperimentNoticeAfterTimeout(
+  experimentIdentifier: string,
+  noticeText: string,
+  showNoticeAfterMs: number,
+  minimumIntervalBetweenNoticesMs: number = ONE_DAY
+): CancelExperimentNoticeCallbackOrUndefined {
+  const configStoreKey = `lastExperimentNotice.${experimentIdentifier}`
+
+  const lastTimeWeShowedNotice = getConfigStore().get(configStoreKey)
+
+  if (lastTimeWeShowedNotice) {
+    if (Date.now() - lastTimeWeShowedNotice < minimumIntervalBetweenNoticesMs) {
+      return undefined
+    }
+  }
+
+  const noticeTimeout = setTimeout(() => {
+    reporter.info(noticeText)
+
+    getConfigStore().set(configStoreKey, Date.now())
+  }, showNoticeAfterMs)
+
+  return function clearNoticeTimeout(): void {
+    clearTimeout(noticeTimeout)
+  }
+}