handle connection errors @ MssqlDriver.

..

src/dialect/mssql/mssql-dialect-config.ts

@@ -62,22 +62,26 @@ export interface TediousConnection {
     name?: string,
     isolationLevel?: number,
   ): void
+  cancel(): boolean
+  close(): void
   commitTransaction(
     callback: (error?: Error | null) => void,
     name?: string,
   ): void
+  connect(callback?: (error?: Error) => void): void
   execSql(request: TediousRequest): void
+  off(event: 'error', listener: (error: unknown) => void): this
+  off(event: string, listener: (...args: any[]) => void): this
+  on(event: 'error', listener: (error: unknown) => void): this
+  on(event: string, listener: (...args: any[]) => void): this
+  once(event: 'end', listener: () => void): this
+  once(event: string, listener: (...args: any[]) => void): this
+  reset(callback: (error?: Error | null) => void): void
   rollbackTransaction(
     callback: (error?: Error | null) => void,
     name?: string,
   ): void
   saveTransaction(callback: (error?: Error | null) => void, name: string): void
-  cancel(): boolean
-  reset(callback: (error?: Error | null) => void): void
-  close(): void
-  once(event: 'end', listener: () => void): this
-  once(event: string, listener: (...args: any[]) => void): this
-  connect(callback?: (error?: Error) => void): void
 }
 
 export type TediousIsolationLevel = Record<string, number>
@@ -104,12 +108,12 @@ export declare class TediousRequest {
       scale?: number
     }> | null,
   ): void
+  off(event: 'row', listener: (columns: any) => void): this
+  off(event: string, listener: (...args: any[]) => void): this
   on(event: 'row', listener: (columns: any) => void): this
   on(event: string, listener: (...args: any[]) => void): this
   once(event: 'requestCompleted', listener: () => void): this
   once(event: string, listener: (...args: any[]) => void): this
-  off(event: 'row', listener: (columns: any) => void): this
-  off(event: string, listener: (...args: any[]) => void): this
   pause(): void
   resume(): void
 }

src/dialect/mssql/mssql-driver.ts

@@ -44,16 +44,12 @@ export class MssqlDriver implements Driver {
     this.#pool = new this.#config.tarn.Pool({
       ...this.#config.tarn.options,
       create: async () => {
-        const connection = await this.#config.tedious.connectionFactory()
+        const tediousConnection = await this.#config.tedious.connectionFactory()
 
-        await new Promise((resolve, reject) =>
-          connection.connect((error) => {
-            if (error) reject(error)
-            else resolve(undefined)
-          }),
-        )
-
-        return new MssqlConnection(connection, this.#config.tedious)
+        return await new MssqlConnection(
+          tediousConnection,
+          this.#config.tedious,
+        ).connect()
       },
       destroy: async (connection) => {
         await connection[PRIVATE_DESTROY_METHOD]()
@@ -104,6 +100,11 @@ class MssqlConnection implements DatabaseConnection {
   constructor(connection: TediousConnection, tedious: Tedious) {
     this.#connection = connection
     this.#tedious = tedious
+
+    this.#connection.on('error', console.error)
+    this.#connection.once('end', () => {
+      this.#connection.off('error', console.error)
+    })
   }
 
   async beginTransaction(settings: TransactionSettings): Promise<void> {
@@ -132,6 +133,21 @@ class MssqlConnection implements DatabaseConnection {
     )
   }
 
+  async connect(): Promise<this> {
+    await new Promise((resolve, reject) => {
+      this.#connection.connect((error) => {
+        if (error) {
+          console.error(error)
+          reject(error)
+        } else {
+          resolve(undefined)
+        }
+      })
+    })
+
+    return this
+  }
+
   async executeQuery<O>(compiledQuery: CompiledQuery): Promise<QueryResult<O>> {
     try {
       const deferred = new Deferred<OnDone<O>>()