fix(MongoInstance): change that stderrHandler also runs error checks

this should fix that the actual error will be shown, even without debug enabled
add function "checkErrorInLine", which is called from "stderrHandler" and "stdoutHandler"

closes #632

Author: hasezoey

packages/mongodb-memory-server-core/src/util/MongoInstance.ts

@@ -519,8 +519,11 @@ export class MongoInstance extends EventEmitter implements ManagerBase {
    * @fires MongoInstance#instanceSTDERR
    */
   stderrHandler(message: string | Buffer): void {
-    this.debug(`stderrHandler: ""${message.toString()}""`); // denoting the STDERR string with double quotes, because the stdout might also use quotes
-    this.emit(MongoInstanceEvents.instanceSTDERR, message);
+    const line: string = message.toString().trim();
+    this.debug(`stderrHandler: ""${line}""`); // denoting the STDERR string with double quotes, because the stdout might also use quotes
+    this.emit(MongoInstanceEvents.instanceSTDERR, line);
+
+    this.checkErrorInLine(line);
   }
 
   /**
@@ -541,6 +544,30 @@ export class MongoInstance extends EventEmitter implements ManagerBase {
     if (/waiting for connections/i.test(line)) {
       this.emit(MongoInstanceEvents.instanceReady);
     }
+
+    this.checkErrorInLine(line);
+
+    // this case needs to be infront of "transition to primary complete", otherwise it might reset "isInstancePrimary" to "false"
+    if (/transition to \w+ from \w+/i.test(line)) {
+      const state = /transition to (\w+) from \w+/i.exec(line)?.[1] ?? 'UNKNOWN';
+      this.emit(MongoInstanceEvents.instanceReplState, state);
+
+      if (state !== 'PRIMARY') {
+        this.isInstancePrimary = false;
+      }
+    }
+    if (/transition to primary complete; database writes are now permitted/i.test(line)) {
+      this.isInstancePrimary = true;
+      this.debug('stdoutHandler: emitting "instancePrimary"');
+      this.emit(MongoInstanceEvents.instancePrimary);
+    }
+  }
+
+  /**
+   * Run Checks on the line if the lines contain any thrown errors
+   * @param line The Line to check
+   */
+  protected checkErrorInLine(line: string) {
     if (/address already in use/i.test(line)) {
       this.emit(
         MongoInstanceEvents.instanceError,
@@ -597,20 +624,6 @@ export class MongoInstance extends EventEmitter implements ManagerBase {
         new StdoutInstanceError('Mongod internal error')
       );
     }
-    // this case needs to be infront of "transition to primary complete", otherwise it might reset "isInstancePrimary" to "false"
-    if (/transition to \w+ from \w+/i.test(line)) {
-      const state = /transition to (\w+) from \w+/i.exec(line)?.[1] ?? 'UNKNOWN';
-      this.emit(MongoInstanceEvents.instanceReplState, state);
-
-      if (state !== 'PRIMARY') {
-        this.isInstancePrimary = false;
-      }
-    }
-    if (/transition to primary complete; database writes are now permitted/i.test(line)) {
-      this.isInstancePrimary = true;
-      this.debug('stdoutHandler: emitting "instancePrimary"');
-      this.emit(MongoInstanceEvents.instancePrimary);
-    }
   }
 }