works

tools/app/promise-learn/src/index.ts

@@ -1,8 +1,14 @@
 import mariadb from 'mariadb'
+import { stringify } from 'querystring'
 
 let conn : mariadb.Connection
 
 
+interface Hero {
+    id: number
+    name: string
+}
+
 class DbHandle {
     private _conn? : mariadb.Connection
 
@@ -17,8 +23,11 @@ class DbHandle {
         })
     }
 
-    public get(stmt : string) : Promise<any> {
-        return this._conn?.query(stmt) ?? Promise.reject(new Error('Connection not ready 1'))
+    public async getHeroes() : Promise<Hero[]> {
+        const result = await this._conn?.query("SELECT id, name FROM hero") ?? Promise.reject(new Error('Connection not ready 1'))
+        return result.map((row: Record<string, unknown>) => { 
+            return { id: row.id, name: row.name ?? 'unknown' } 
+        })
     }
 
     public close() : Promise<void> {
@@ -43,10 +52,13 @@ dbHandle.connect()
 
 async function exec() : Promise<void> {
     const dbHandle = new DbHandle()
-    await dbHandle.connect()
-    const result = await dbHandle.get("SELECT * FROM hero")
-    console.log(result)
-    await dbHandle.close()
+    try {
+        await dbHandle.connect()
+        const heroes : Hero[] = await dbHandle.getHeroes()
+        console.log(heroes)
+    } finally {
+        await dbHandle.close()
+    }
 }
 
 exec().catch((err) => console.log(err.message))