feat(Email Trigger (IMAP) Node): Migrate from imap-simple to @n8n/imap (#8899)

Co-authored-by: Jonathan Bennetts <jonathan.bennetts@gmail.com>

packages/@n8n/imap/src/index.ts

@@ -0,0 +1,99 @@
+/* eslint-disable @typescript-eslint/no-unsafe-member-access */
+/* eslint-disable @typescript-eslint/no-use-before-define */
+import Imap from 'imap';
+import { ImapSimple } from './ImapSimple';
+import { ConnectionClosedError, ConnectionEndedError, ConnectionTimeoutError } from './errors';
+import type { ImapSimpleOptions, MessagePart } from './types';
+
+/**
+ * Connect to an Imap server, returning an ImapSimple instance, which is a wrapper over node-imap to simplify it's api for common use cases.
+ */
+export async function connect(options: ImapSimpleOptions): Promise<ImapSimple> {
+	const authTimeout = options.imap.authTimeout ?? 2000;
+	options.imap.authTimeout = authTimeout;
+
+	const imap = new Imap(options.imap);
+
+	return await new Promise<ImapSimple>((resolve, reject) => {
+		const cleanUp = () => {
+			imap.removeListener('ready', imapOnReady);
+			imap.removeListener('error', imapOnError);
+			imap.removeListener('close', imapOnClose);
+			imap.removeListener('end', imapOnEnd);
+		};
+
+		const imapOnReady = () => {
+			cleanUp();
+			resolve(new ImapSimple(imap));
+		};
+
+		const imapOnError = (e: Error & { source?: string }) => {
+			if (e.source === 'timeout-auth') {
+				e = new ConnectionTimeoutError(authTimeout);
+			}
+
+			cleanUp();
+			reject(e);
+		};
+
+		const imapOnEnd = () => {
+			cleanUp();
+			reject(new ConnectionEndedError());
+		};
+
+		const imapOnClose = () => {
+			cleanUp();
+			reject(new ConnectionClosedError());
+		};
+
+		imap.once('ready', imapOnReady);
+		imap.once('error', imapOnError);
+		imap.once('close', imapOnClose);
+		imap.once('end', imapOnEnd);
+
+		if (options.onMail) {
+			imap.on('mail', options.onMail);
+		}
+
+		if (options.onExpunge) {
+			imap.on('expunge', options.onExpunge);
+		}
+
+		if (options.onUpdate) {
+			imap.on('update', options.onUpdate);
+		}
+
+		imap.connect();
+	});
+}
+
+/**
+ * Given the `message.attributes.struct`, retrieve a flattened array of `parts` objects that describe the structure of
+ * the different parts of the message's body. Useful for getting a simple list to iterate for the purposes of,
+ * for example, finding all attachments.
+ *
+ * Code taken from http://stackoverflow.com/questions/25247207/how-to-read-and-save-attachments-using-node-imap
+ *
+ * @returns {Array} a flattened array of `parts` objects that describe the structure of the different parts of the
+ *  message's body
+ */
+export function getParts(
+	/** The `message.attributes.struct` value from the message you wish to retrieve parts for. */
+	// eslint-disable-next-line @typescript-eslint/no-explicit-any
+	struct: any,
+	/** The list of parts to push to. */
+	parts: MessagePart[] = [],
+): MessagePart[] {
+	for (let i = 0; i < struct.length; i++) {
+		if (Array.isArray(struct[i])) {
+			getParts(struct[i], parts);
+		} else if (struct[i].partID) {
+			parts.push(struct[i] as MessagePart);
+		}
+	}
+	return parts;
+}
+
+export * from './ImapSimple';
+export * from './errors';
+export * from './types';