diff --git a/packages/firebase-crashlytics/index.android.ts b/packages/firebase-crashlytics/index.android.ts
index b5879ff0..d0d3059c 100644
--- a/packages/firebase-crashlytics/index.android.ts
+++ b/packages/firebase-crashlytics/index.android.ts
@@ -73,7 +73,7 @@ export class Crashlytics implements ICrashlytics {
 			StackTrace.fromError(error).then((stack) => {
 				const traceElements = Array.create('java.lang.StackTraceElement', stack.length);
 				stack.forEach((item, i) => {
-					traceElements[i] = new java.lang.StackTraceElement('', item.functionName, item.fileName, -1);
+					traceElements[i] = new java.lang.StackTraceElement('', item.functionName || '(anonymous)', item.fileName, -1);
 				});
 				const t = new java.lang.Throwable(error.message);
 				t.setStackTrace(traceElements);
diff --git a/packages/firebase-crashlytics/index.ios.ts b/packages/firebase-crashlytics/index.ios.ts
index ada30a9d..925dc452 100644
--- a/packages/firebase-crashlytics/index.ios.ts
+++ b/packages/firebase-crashlytics/index.ios.ts
@@ -67,7 +67,7 @@ export class Crashlytics implements ICrashlytics {
 			StackTrace.fromError(error).then((stack) => {
 				const traceElements = [];
 				stack.forEach((item, i) => {
-					traceElements[i] = FIRStackFrame.stackFrameWithSymbolFileLine(item.functionName, item.fileName, item.lineNumber);
+					traceElements[i] = FIRStackFrame.stackFrameWithSymbolFileLine(item.functionName || '(anonymous)', item.fileName, item.lineNumber);
 				});
 				const e = FIRExceptionModel.exceptionModelWithNameReason('JavaScriptError', error.message);
 				this.native.recordExceptionModel(e);