Encode Automerge docs for Camino CRDT writes

src/crdt-automerge.ts

@@ -12,10 +12,32 @@ type AutomergeFieldDoc = {
   value: unknown;
 };
 
-const bytesToBase64 = (value: Uint8Array) =>
-  Buffer.from(value).toString("base64");
+export type CaminoAutomergeDoc<T = unknown> = Automerge.Doc<{
+  value: T;
+}>;
 
-const base64ToBytes = (value: string) => Buffer.from(value, "base64");
+const bytesToBase64 = (value: Uint8Array) => {
+  if (typeof Buffer !== "undefined") {
+    return Buffer.from(value).toString("base64");
+  }
+  let binary = "";
+  for (const byte of value) {
+    binary += String.fromCharCode(byte);
+  }
+  return btoa(binary);
+};
+
+const base64ToBytes = (value: string) => {
+  if (typeof Buffer !== "undefined") {
+    return Buffer.from(value, "base64");
+  }
+  const binary = atob(value);
+  const bytes = new Uint8Array(binary.length);
+  for (let index = 0; index < binary.length; index += 1) {
+    bytes[index] = binary.charCodeAt(index);
+  }
+  return bytes;
+};
 
 export const isCaminoCrdtEnvelope = (
   value: unknown,
@@ -65,16 +87,38 @@ export const createAutomergeFieldValue = (
 ): CaminoCrdtEnvelope =>
   saveAutomergeFieldDoc(Automerge.from<AutomergeFieldDoc>({ value }), type);
 
-export const normalizeAutomergeFieldValue = (
+export const isAutomergeFieldDoc = (
+  value: unknown,
+): value is Automerge.Doc<AutomergeFieldDoc> => {
+  if (!value || typeof value !== "object") {
+    return false;
+  }
+  try {
+    Automerge.getHeads(value as Automerge.Doc<AutomergeFieldDoc>);
+    return true;
+  } catch {
+    return false;
+  }
+};
+
+export const encodeAutomergeFieldWrite = (
   value: unknown,
   type: string,
 ): CaminoCrdtEnvelope => {
   if (isCaminoCrdtEnvelope(value)) {
     return saveAutomergeFieldDoc(loadAutomergeFieldDoc(value, type), type);
   }
+  if (isAutomergeFieldDoc(value)) {
+    return saveAutomergeFieldDoc(value, type);
+  }
   return createAutomergeFieldValue(value, type);
 };
 
+export const normalizeAutomergeFieldValue = (
+  value: unknown,
+  type: string,
+): CaminoCrdtEnvelope => encodeAutomergeFieldWrite(value, type);
+
 export const materializeAutomergeFieldValue = (
   value: CaminoCrdtEnvelope,
   type: string,