diff --git a/src/api-log-appender.ts b/src/api-log-appender.ts
index 2ab1c84..b13ed13 100644
--- a/src/api-log-appender.ts
+++ b/src/api-log-appender.ts
@@ -5,7 +5,7 @@ export class ApiLogAppender implements LogAppender {
   public batchSize = 10
   public minimumTimePassedInSec = 60
   public maximumTimePassedInSec = 120
-  public threshold = LogLevel.ALL
+  public threshold: LogLevel
 
   private msgBuffer: FlattenedLogMessage[] = []
   private lastSent = 0
@@ -16,9 +16,7 @@ export class ApiLogAppender implements LogAppender {
     threshold?: LogLevel
   ) {
     setTimeout(this.checkPost, 1000)
-    if (threshold) {
-      this.threshold = threshold
-    }
+    this.threshold = threshold ?? LogLevel.ALL
   }
 
   public appendMessage(msg: LogMessage): void {
diff --git a/src/buffer-log-appender.ts b/src/buffer-log-appender.ts
new file mode 100644
index 0000000..c802722
--- /dev/null
+++ b/src/buffer-log-appender.ts
@@ -0,0 +1,21 @@
+import type { LogAppender } from './log-appender'
+import { LogLevel, type LogMessage } from './log-message'
+
+export class BufferLogAppender implements LogAppender {
+  public threshold: LogLevel
+  public buffer: LogMessage[]
+
+  constructor(buffer?: LogMessage[], threshold?: LogLevel) {
+    this.buffer = buffer ?? []
+    this.threshold = threshold ?? LogLevel.ALL
+  }
+
+  public appendMessage(msg: LogMessage): void {
+    if (this.threshold && msg.level < this.threshold) return
+    else this.buffer.push(msg)
+  }
+
+  public clearBuffer(): void {
+    this.buffer.length = 0
+  }
+}
diff --git a/src/console-log-appender.ts b/src/console-log-appender.ts
index 36b77bf..e4e54eb 100644
--- a/src/console-log-appender.ts
+++ b/src/console-log-appender.ts
@@ -18,16 +18,12 @@ import { LogAppender } from './log-appender'
  * data for inspection in the browser's developer tools.
  */
 export class ConsoleLogAppender implements LogAppender {
-  public threshold = LogLevel.ALL
-  public formatter: LogMessageFormatter = flattenMessage
+  public threshold: LogLevel
+  public formatter: LogMessageFormatter
 
   constructor(threshold?: LogLevel, formatter?: LogMessageFormatter) {
-    if (threshold) {
-      this.threshold = threshold
-    }
-    if (formatter) {
-      this.formatter = formatter
-    }
+    this.threshold = threshold ?? LogLevel.ALL
+    this.formatter = formatter ?? flattenMessage
   }
 
   public appendMessage(msg: LogMessage): void {