Add validation for undefined endpoint in TypeScript setEndpoint method

Previously, calling setEndpoint() with undefined would throw a confusing
TypeError when trying to call .startsWith() on undefined. This adds proper
validation to check if the endpoint is null, undefined, or not a string
before checking its format, providing a clear error message.

Changes:
- Add endpoint validation before .startsWith() check
- Throw descriptive error: "Endpoint must be a valid string"
- Applied to Node, Web, Deno, and React Native TypeScript clients

Fixes the weird error when endpoint is undefined.

Author: ChiragAgg5k

templates/deno/src/client.ts.twig

@@ -46,6 +46,10 @@ export class Client {
      * @return this
      */
     setEndpoint(endpoint: string): this {
+        if (!endpoint || typeof endpoint !== 'string') {
+            throw new {{spec.title | caseUcfirst}}Exception('Endpoint must be a valid string');
+        }
+
         if (!endpoint.startsWith('http://') && !endpoint.startsWith('https://')) {
             throw new {{spec.title | caseUcfirst}}Exception('Invalid endpoint URL: ' + endpoint);
         }

templates/node/src/client.ts.twig

@@ -96,6 +96,10 @@ class Client {
      * @returns {this}
      */
     setEndpoint(endpoint: string): this {
+        if (!endpoint || typeof endpoint !== 'string') {
+            throw new {{spec.title | caseUcfirst}}Exception('Endpoint must be a valid string');
+        }
+
         if (!endpoint.startsWith('http://') && !endpoint.startsWith('https://')) {
             throw new {{spec.title | caseUcfirst}}Exception('Invalid endpoint URL: ' + endpoint);
         }

templates/react-native/src/client.ts.twig

@@ -129,6 +129,10 @@ class Client {
      * @returns {this}
      */
     setEndpoint(endpoint: string): this {
+        if (!endpoint || typeof endpoint !== 'string') {
+            throw new {{spec.title | caseUcfirst}}Exception('Endpoint must be a valid string');
+        }
+
         if (!endpoint.startsWith('http://') && !endpoint.startsWith('https://')) {
             throw new {{spec.title | caseUcfirst}}Exception('Invalid endpoint URL: ' + endpoint);
         }

templates/web/src/client.ts.twig

@@ -334,6 +334,10 @@ class Client {
      * @returns {this}
      */
     setEndpoint(endpoint: string): this {
+        if (!endpoint || typeof endpoint !== 'string') {
+            throw new {{spec.title | caseUcfirst}}Exception('Endpoint must be a valid string');
+        }
+
         if (!endpoint.startsWith('http://') && !endpoint.startsWith('https://')) {
             throw new {{spec.title | caseUcfirst}}Exception('Invalid endpoint URL: ' + endpoint);
         }