started to convert to typescript

back/mails/utils/envelopeUtils.ts

@@ -0,0 +1,16 @@
+export function nbMembers(envelope) {
+    return getMembers(envelope).length;
+}
+
+export function getMembers(envelope) {
+    const members: { mailbox: string; host: string }[] = [];
+    const fields = ["from", "to", "sender", "replyTo", "cc", "bcc"];
+    fields.forEach((field) => {
+        if (!envelope[field]) return;
+        envelope[field].forEach((member) => {
+            if (members.find((m) => m.mailbox === member.mailbox && m.host === member.host)) return;
+            members.push(member);
+        });
+    });
+    return members;
+}