Refactor Class.getTeachers and Class.getStudents into their own functions

lib/Class.js

@@ -74,28 +74,6 @@ class Class {
 				classId = ?;
 		`;
 
-		const teacherSQL = `
-			select
-				a.accountId as id
-			from
-				account a
-				join accountClassLink acl using (accountId)
-			where
-				acl.classId = ?;
-
-		`;
-
-		const studentSQL = `
-			select
-				s.studentId as id
-			from
-				student s
-				join studentClassLink scl using (studentId)
-			where
-				scl.classId = ?;
-
-		`;
-
 		return (async () => {
 			const record = await this.#conn.runQuery(sql, [
 				classId
@@ -107,25 +85,13 @@ class Class {
 			for (const [ k, v ] of Object.entries(record[0]))
 				this[k] = v;
 
-			const [ teacherRes, studentRes ] = await Promise.all([
-				this.#conn.runQuery(teacherSQL, [
-					classId
-				]),
-				this.#conn.runQuery(studentSQL, [
-					classId
-				])
-			]);
-
-			this.teacherIds = teacherRes.map(record => record.id);
-			this.studentIds = studentRes.map(record => record.id);
-
 			const [
 				teachers,
 				students,
 				subject,
 			] = await Promise.all([
-				this.getUsers(this.teacherIds, 'account'),
+				this.getTeachers(),
-				this.getUsers(this.studentIds, 'student'),
+				this.getStudents(),
 				this.getSubject()
 			]);
 
@@ -141,6 +107,47 @@ class Class {
 		return new (require('./Subject'))(this.#conn, this.subjectId);
 	}
 
+	async getTeachers() {
+		const sql = `
+			select
+				a.accountId as id
+			from
+				account a
+				join accountClassLink acl using (accountId)
+			where
+				acl.classId = ?;
+
+		`;
+
+		const res = await this.#conn.runQuery(sql, [ this.id ]);
+
+		this.teacherIds = res.map(record => record.id);
+
+		this.teachers = await this.getUsers(this.teacherIds, 'account');
+
+		return this.teachers;
+	}
+
+	async getStudents() {
+		const sql = `
+			select
+				s.studentId as id
+			from
+				student s
+				join studentClassLink scl using (studentId)
+			where
+				scl.classId = ?;
+		`;
+
+		const res = await this.#conn.runQuery(sql, [ this.id ]);
+
+		this.studentIds = res.map(record => record.id);
+
+		this.students = await this.getUsers(this.studentIds, 'student');
+
+		return this.students;
+	}
+
 	getUsers(ids, type) {
 		const types = {
 			account: 'Account',