refactor(transaction): asyncify methods (#12156)

lib/transaction.js

@@ -64,7 +64,7 @@ class Transaction {
     } finally {
       this.finished = 'commit';
       if (!this.parent) {
-        await this.cleanup();
+        this.cleanup();
       }
       for (const hook of this._afterCommitHooks) {
         await hook.apply(this, [this]);
@@ -77,30 +77,30 @@ class Transaction {
    *
    * @returns {Promise}
    */
-  rollback() {
+  async rollback() {
     if (this.finished) {
-      return Promise.reject(new Error(`Transaction cannot be rolled back because it has been finished with state: ${this.finished}`));
+      throw new Error(`Transaction cannot be rolled back because it has been finished with state: ${this.finished}`);
     }
 
     if (!this.connection) {
-      return Promise.reject(new Error('Transaction cannot be rolled back because it never started'));
+      throw new Error('Transaction cannot be rolled back because it never started');
     }
 
     this._clearCls();
 
-    return this
-      .sequelize
-      .getQueryInterface()
-      .rollbackTransaction(this, this.options)
-      .finally(() => {
-        if (!this.parent) {
-          return this.cleanup();
-        }
-        return this;
-      });
+    try {
+      return await this
+        .sequelize
+        .getQueryInterface()
+        .rollbackTransaction(this, this.options);
+    } finally {
+      if (!this.parent) {
+        this.cleanup();
+      }
+    }
   }
 
-  prepareEnvironment(useCLS) {
+  async prepareEnvironment(useCLS) {
     let connectionPromise;
 
     if (useCLS === undefined) {
@@ -117,47 +117,49 @@ class Transaction {
       connectionPromise = this.sequelize.connectionManager.getConnection(acquireOptions);
     }
 
-    return connectionPromise
-      .then(connection => {
-        this.connection = connection;
-        this.connection.uuid = this.id;
-      })
-      .then(() => {
-        return this.begin()
-          .then(() => this.setDeferrable())
-          .catch(setupErr => this.rollback().finally(() => {
-            throw setupErr;
-          }));
-      })
-      .then(result => {
-        if (useCLS && this.sequelize.constructor._cls) {
-          this.sequelize.constructor._cls.set('transaction', this);
-        }
-        return Promise.resolve(null).then(() => result);
-      });
+    let result;
+    const connection = await connectionPromise;
+    this.connection = connection;
+    this.connection.uuid = this.id;
+
+    try {
+      await this.begin();
+      result = await this.setDeferrable();
+    } catch (setupErr) {
+      try {
+        result = await this.rollback();
+      } finally {
+        throw setupErr; // eslint-disable-line no-unsafe-finally
+      }
+    }
+
+    if (useCLS && this.sequelize.constructor._cls) {
+      this.sequelize.constructor._cls.set('transaction', this);
+    }
+
+    return result;
   }
 
-  setDeferrable() {
+  async setDeferrable() {
     if (this.options.deferrable) {
-      return this
+      return await this
         .sequelize
         .getQueryInterface()
         .deferConstraints(this, this.options);
     }
   }
 
-  begin() {
+  async begin() {
     const queryInterface = this.sequelize.getQueryInterface();
 
     if ( this.sequelize.dialect.supports.settingIsolationLevelDuringTransaction ) {
-      return queryInterface.startTransaction(this, this.options).then(() => {
-        return queryInterface.setIsolationLevel(this, this.options.isolationLevel, this.options);
-      });
+      await queryInterface.startTransaction(this, this.options);
+      return queryInterface.setIsolationLevel(this, this.options.isolationLevel, this.options);
     }
 
-    return queryInterface.setIsolationLevel(this, this.options.isolationLevel, this.options).then(() => {
-      return queryInterface.startTransaction(this, this.options);
-    });
+    await queryInterface.setIsolationLevel(this, this.options.isolationLevel, this.options);
+
+    return queryInterface.startTransaction(this, this.options);
   }
 
   cleanup() {