refactor: put the default host in a variable and reuse it

The default host 'http://127.0.0.1:11434' is hardcoded in
multiple places, So, Put it in one variable in a central place
(`src/defaultHost.ts` file) and reuse it in those places.

src/browser.ts

@@ -25,6 +25,7 @@ import type {
   ShowResponse,
   StatusResponse,
 } from './interfaces.js'
+import { defaultHost } from './defaultHost.js'
 
 export class Ollama {
   protected readonly config: Config
@@ -38,7 +39,7 @@ export class Ollama {
     }
 
     if (!config?.proxy) {
-      this.config.host = utils.formatHost(config?.host ?? 'http://127.0.0.1:11434')
+      this.config.host = utils.formatHost(config?.host ?? defaultHost)
     }
 
     this.fetch = config?.fetch ?? fetch

src/defaultHost.ts

@@ -0,0 +1,2 @@
+export const defaulPort = '11434';
+export const defaultHost = `http://127.0.0.1:${defaulPort}`;

src/utils.ts

@@ -1,5 +1,6 @@
 import { version } from './version.js'
 import type { ErrorResponse, Fetch } from './interfaces.js'
+import { defaulPort, defaultHost } from './defaultHost.js'
 
 /**
  * An error class for response errors.
@@ -268,7 +269,7 @@ export const parseJSON = async function* <T = unknown>(
  */
 export const formatHost = (host: string): string => {
   if (!host) {
-    return 'http://127.0.0.1:11434'
+    return defaultHost
   }
 
   let isExplicitProtocol = host.includes('://')
@@ -288,7 +289,7 @@ export const formatHost = (host: string): string => {
   let port = url.port
   if (!port) {
     if (!isExplicitProtocol) {
-      port = '11434'
+      port = defaulPort
     } else {
       // Assign default ports based on the protocol
       port = url.protocol === 'https:' ? '443' : '80'

test/index.test.ts

@@ -1,9 +1,10 @@
 import { describe, it, expect } from 'vitest'
 import { formatHost } from '../src/utils'
+import { defaultHost } from '../src/defaultHost'
 
 describe('formatHost Function Tests', () => {
   it('should return default URL for empty string', () => {
-    expect(formatHost('')).toBe('http://127.0.0.1:11434')
+    expect(formatHost('')).toBe(defaultHost)
   })
 
   it('should parse plain IP address', () => {