migrate to typescript

src/lib/serial/line-break-transformer.ts

@@ -0,0 +1,18 @@
+export class LineBreakTransformer {
+  private chunks = ""
+
+  // noinspection JSUnusedGlobalSymbols
+  transform(chunk: string, controller: TransformStreamDefaultController) {
+    this.chunks += chunk
+    const lines = this.chunks.split("\r\n")
+    this.chunks = lines.pop()!
+    for (const line of lines) {
+      controller.enqueue(line)
+    }
+  }
+
+  // noinspection JSUnusedGlobalSymbols
+  flush(controller: TransformStreamDefaultController) {
+    controller.enqueue(this.chunks)
+  }
+}