From 863e3fe94eede6f7b2cc286df0b2c12763de5c05 Mon Sep 17 00:00:00 2001
From: Nikita Sivukhin <sivukhin@turso.tech>
Date: Thu, 2 Oct 2025 16:01:23 +0400
Subject: [PATCH] make url parameter to accept either string or function

---
 .../javascript/sync/packages/common/run.ts     | 14 ++++++++++++--
 .../javascript/sync/packages/common/types.ts   | 18 +++++++++++-------
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/bindings/javascript/sync/packages/common/run.ts b/bindings/javascript/sync/packages/common/run.ts
index 4d1d1c969..554c5ff61 100644
--- a/bindings/javascript/sync/packages/common/run.ts
+++ b/bindings/javascript/sync/packages/common/run.ts
@@ -22,15 +22,25 @@ async function process(opts: RunOpts, io: ProtocolIo, request: any) {
     const requestType = request.request();
     const completion = request.completion();
     if (requestType.type == 'Http') {
+        let url: string | null = null;
+        if (typeof opts.url == "function") {
+            url = opts.url();
+        } else {
+            url = opts.url;
+        }
+        if (url == null) {
+            completion.poison(`url is empty - sync is paused`);
+            return;
+        }
         try {
-            let headers = typeof opts.headers === "function" ? opts.headers() : opts.headers;
+            let headers = typeof opts.headers === "function" ? await opts.headers() : opts.headers;
             if (requestType.headers != null && requestType.headers.length > 0) {
                 headers = { ...opts.headers };
                 for (let header of requestType.headers) {
                     headers[header[0]] = header[1];
                 }
             }
-            const response = await fetch(`${opts.url}${requestType.path}`, {
+            const response = await fetch(`${url}${requestType.path}`, {
                 method: requestType.method,
                 headers: headers,
                 body: requestType.body != null ? new Uint8Array(requestType.body) : null,
diff --git a/bindings/javascript/sync/packages/common/types.ts b/bindings/javascript/sync/packages/common/types.ts
index ee3e77a87..98f0f0c69 100644
--- a/bindings/javascript/sync/packages/common/types.ts
+++ b/bindings/javascript/sync/packages/common/types.ts
@@ -61,7 +61,7 @@ export interface EncryptionOpts {
     // base64 encoded encryption key (must be either 16 or 32 bytes depending on the cipher)
     key: string,
     // encryption cipher algorithm
-    cipher: 'aes256gcm' | 'aes128gcm' | 'chacha20poly1305'
+    cipher: 'aes256gcm' | 'aes128gcm' | 'chacha20poly1305' | 'aegis256'
 }
 export interface DatabaseOpts {
     /**
@@ -73,22 +73,26 @@ export interface DatabaseOpts {
     /**
      * optional url of the remote database (e.g. libsql://db-org.turso.io)
      * (if omitted - local-only database will be created)
+     * 
+     * you can also promide function which will return URL or null
+     * in this case local database will be created and sync will be "switched-on" whenever the url will return non-empty value
+     * note, that all other parameters (like encryption) must be set in advance in order for the "deferred" sync to work properly
      */
-    url?: string;
+    url?: string | (() => string | null);
     /**
      * auth token for the remote database
      * (can be either static string or function which will provide short-lived credentials for every new request)
      */
-    authToken?: string | (() => string);
+    authToken?: string | (() => Promise<string>);
     /**
      * arbitrary client name which can be used to distinguish clients internally
      * the library will gurantee uniquiness of the clientId by appending unique suffix to the clientName
      */
     clientName?: string;
     /**
-     * optional encryption parameters if cloud database were encrypted by default
+     * optional remote encryption parameters if cloud database were encrypted by default
      */
-    encryption?: EncryptionOpts;
+    remoteEncryption?: EncryptionOpts;
     /**
      * optional callback which will be called for every mutation before sending it to the remote
      * this callback can transform the update in order to support complex conflict resolution strategy
@@ -136,8 +140,8 @@ export interface DatabaseStats {
 
 export interface RunOpts {
     preemptionMs: number,
-    url: string,
-    headers: { [K: string]: string } | (() => { [K: string]: string })
+    url: string | (() => string | null),
+    headers: { [K: string]: string } | (() => Promise<{ [K: string]: string }>)
     transform?: Transform,
 }