Add basic fetch example extracted from wrapper repo

typescript/fetch/src/basic/example.ts

@@ -0,0 +1,87 @@
+/**
+ * Example: Using OpenRouter with raw fetch API
+ *
+ * This example demonstrates how to make direct HTTP requests to OpenRouter's API
+ * using the native fetch API without any additional libraries.
+ */
+
+import type { ChatCompletionResponse } from '@openrouter-examples/shared/types';
+
+// OpenRouter API endpoint
+const OPENROUTER_API_URL = 'https://openrouter.ai/api/v1/chat/completions';
+
+// Request payload following OpenAI-compatible chat completions format
+const requestBody = {
+  model: 'openai/gpt-4o-mini',
+  messages: [
+    {
+      role: 'user',
+      content: 'Write a haiku about TypeScript',
+    },
+  ],
+};
+
+console.log('=== OpenRouter Raw Fetch Example ===\n');
+console.log('Request:');
+console.log(`URL: ${OPENROUTER_API_URL}`);
+console.log('Model:', requestBody.model);
+console.log('Message:', requestBody.messages[0]?.content);
+console.log();
+
+try {
+  // Ensure API key is available
+  if (!process.env.OPENROUTER_API_KEY) {
+    throw new Error('OPENROUTER_API_KEY environment variable is not set');
+  }
+
+  // Make the HTTP POST request to OpenRouter
+  const response = await fetch(OPENROUTER_API_URL, {
+    method: 'POST',
+    headers: {
+      // Required: Authorization header with your API key
+      Authorization: `Bearer ${process.env.OPENROUTER_API_KEY}`,
+      // Required: Content type for JSON payload
+      'Content-Type': 'application/json',
+      // Optional but recommended: Identify your app
+      'HTTP-Referer': 'https://github.com/openrouter/examples',
+      'X-Title': 'OpenRouter Fetch Example',
+    },
+    body: JSON.stringify(requestBody),
+  });
+
+  // Check if the request was successful
+  if (!response.ok) {
+    const errorText = await response.text();
+    throw new Error(`HTTP error! status: ${response.status}, body: ${errorText}`);
+  }
+
+  // Parse the JSON response
+  const data = (await response.json()) as ChatCompletionResponse;
+
+  // Display the response
+  console.log('Response:');
+  console.log('Status:', response.status, response.statusText);
+  console.log('Model used:', data.model);
+  console.log('\nGenerated content:');
+  console.log(data.choices[0]?.message?.content);
+  console.log('\nUsage stats:');
+  console.log('- Prompt tokens:', data.usage.prompt_tokens);
+  console.log('- Completion tokens:', data.usage.completion_tokens);
+  console.log('- Total tokens:', data.usage.total_tokens);
+
+  // Optional: Show raw response structure
+  if (process.env.DEBUG) {
+    console.log('\nFull response object:');
+    console.log(JSON.stringify(data, null, 2));
+  }
+} catch (error) {
+  console.error('Error making request to OpenRouter:');
+
+  if (error instanceof Error) {
+    console.error('Error message:', error.message);
+  } else {
+    console.error('Unknown error:', error);
+  }
+
+  process.exit(1);
+}