fix: retry if eval fails (#160)

Author: mifi

src/lib.ts

@@ -103,6 +103,27 @@ class RedisStore implements Store {
     this.windowMs = options.windowMs;
   }
 
+  async runCommandWithRetry(key: string) {
+    const evalCommand = async () =>
+      this.sendCommand(
+        "EVALSHA",
+        await this.loadedScriptSha1,
+        "1",
+        this.prefixKey(key),
+        this.resetExpiryOnChange ? "1" : "0",
+        this.windowMs.toString()
+      );
+
+    try {
+      const result = await evalCommand();
+      return result;
+    } catch {
+      // TODO: distinguish different error types
+      this.loadedScriptSha1 = this.loadScript();
+      return evalCommand();
+    }
+  }
+
   /**
    * Method to increment a client's hit counter.
    *
@@ -111,14 +132,7 @@ class RedisStore implements Store {
    * @returns {IncrementResponse} - The number of hits and reset time for that client
    */
   async increment(key: string): Promise<IncrementResponse> {
-    const results = await this.sendCommand(
-      "EVALSHA",
-      await this.loadedScriptSha1,
-      "1",
-      this.prefixKey(key),
-      this.resetExpiryOnChange ? "1" : "0",
-      this.windowMs.toString()
-    );
+    const results = await this.runCommandWithRetry(key);
 
     if (!Array.isArray(results)) {
       throw new TypeError("Expected result to be array of values");