Implemented Account.getUserByEmail

lib/User.js

@@ -111,7 +111,28 @@ class User {
 		return res;
 	}
 
-	static getUserByEmail() {
+	static async getUserByEmail(email) {
+		const conn = await new DatabaseConnectionPool();
+		const types = [ 'account', 'student', 'parent' ];
+
+		for (const type of types) {
+			const sql = `
+				select ${type}id as id
+				from ${type}
+				where email = ?;
+			`;
+
+			const id = (await conn.runQuery(sql, [
+				email
+			]))?.[0]?.['id'];
+
+			if (typeof id !== 'undefined') {
+				const className =
+					`${type.substring(0, 1).toUpperCase()}`
+					+ `${type.substring(1)}`;
+				return new (require(`./${className}`))(id);
+			}
+		}
 
 	}
 }