make defaultChainId optional

Author: tanguyenvn

packages/no-modal/src/base/core/IWeb3Auth.ts

@@ -59,10 +59,9 @@ export interface IWeb3AuthCoreOptions {
   chains?: CustomChainConfig[];
 
   /**
-   * TODO: should we make this mandatory? Is it possible to configure it from Dashboard?
    * default chain Id to use
    */
-  defaultChainId: string;
+  defaultChainId?: string;
 
   /**
    * setting to true will enable logs

packages/no-modal/src/noModal.ts

@@ -83,7 +83,7 @@ export class Web3AuthNoModal extends SafeEventEmitter<Web3AuthNoModalEvents> imp
       })),
     };
 
-    this.currentChainId = options.defaultChainId;
+    this.currentChainId = options.defaultChainId || chains[0].chainId;
   }
 
   get currentChain(): CustomChainConfig {
@@ -230,10 +230,10 @@ export class Web3AuthNoModal extends SafeEventEmitter<Web3AuthNoModalEvents> imp
 
   protected initCachedConnectorAndChainId() {
     this.cachedConnector = storageAvailable(this.storage) ? window[this.storage].getItem(CONNECTOR_CACHE_KEY) : null;
-    // init chainId using cached chainId if it exists and is valid, otherwise use the first chain
+    // init chainId using cached chainId if it exists and is valid, otherwise use the defaultChainId or the first chain
     const cachedChainId = storageAvailable(this.storage) ? window[this.storage].getItem(CURRENT_CHAIN_CACHE_KEY) : null;
     const isCachedChainIdValid = cachedChainId && this.coreOptions.chains.some((chain) => chain.chainId === cachedChainId);
-    this.currentChainId = isCachedChainIdValid ? cachedChainId : this.coreOptions.defaultChainId;
+    this.currentChainId = isCachedChainIdValid ? cachedChainId : this.coreOptions.defaultChainId || this.coreOptions.chains[0].chainId;
   }
 
   protected async setupCommonJRPCProvider() {