await

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

@@ -1,31 +1,63 @@
-const mariadb = require('mariadb')
+import mariadb from 'mariadb'
 
 let conn : mariadb.Connection
 
-mariadb.createConnection({
-        host: 'database',
-        user: 'heroes',
-        password: 'test123',
-        database: 'heroes'
-    })
-    .then(conn => {
-        conn.query("SELECT * FROM hero")
-            .then((rows) => {
-                console.log(rows)
-                return rows
-            })
-            .then((res) => {
-                console.log(res)
-                conn.end()
-            })
-            .catch(err => {
-                console.log(err)
-                conn.end()
-            })
-    })
-    .catch(err => {
-        console.log('not connected')
-    })
+
+class DbHandle {
+    private _conn? : mariadb.Connection
+
+    public constructor() {}
+
+    public async connect() : Promise<void> {
+        this._conn = await mariadb.createConnection({
+            host: '172.16.10.18',
+            user: 'heroes',
+            password: 'test123',
+            database: 'heroes'
+        })
+    }
+
+    public get(stmt : string) : Promise<any> {
+        return this._conn?.query(stmt) ?? Promise.reject(new Error('Connection not ready 1'))
+    }
+
+    public close() : Promise<void> {
+        return this._conn?.end() ?? Promise.reject(new Error('Connection not ready 2'))
+    }
+}
 
 
 
+/*
+const dbHandle = new DbHandle()
+dbHandle.connect()
+    .then(() => dbHandle.get("SELECT * FROM hero"))
+    .then((result) => { 
+        console.log(result)
+        return dbHandle.close() 
+    })
+    .catch((err) => {
+        console.log(err)
+    })
+*/
+
+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()
+}
+
+exec().catch((err) => console.log(err.message))
+
+/*
+dbHandle.get("SELECT * FROM hero")
+    .then((result) => { 
+        console.log(result)
+        return dbHandle.close() 
+    })
+    .catch((err) => {
+        console.log(err.message)
+    })
+*/