Static method to run function in CLS context

lib/sequelize.js

@@ -975,18 +975,11 @@ class Sequelize {
     // testhint argsConform.end
 
     const transaction = new Transaction(this, options);
-    const ns = Sequelize._cls;
 
     if (!autoCallback) return transaction.prepareEnvironment().return(transaction);
 
     // autoCallback provided
-    const wrapper = ns ? function(fn) {
-      var promise;
-      ns.run(() => promise = fn());
-      return promise;
-    } : function(fn) { return fn(); };
-
-    return wrapper(() =>
+    return Sequelize._clsRun(() =>
       transaction.prepareEnvironment().then(() =>
         autoCallback(transaction)
       ).tap(() =>
@@ -1023,6 +1016,23 @@ class Sequelize {
     return this;
   }
 
+  /**
+   * Run function in CLS context.
+   * If no CLS context in use, just runs the function normally
+   *
+   * @private
+   * @param {Function} fn Function to run
+   * @returns {*} Return value of function
+   */
+  static _clsRun(fn) {
+    var ns = Sequelize._cls;
+    if (!ns) return fn();
+
+    var res;
+    ns.run((context) => res = fn(context));
+    return res;
+  }
+
   static get cls() {
     return this._cls;
   }