Adds localhost to the clusterApiUrl utility with the option to change…

… the port.

web3.js/src/util/cluster.ts

@@ -3,26 +3,32 @@ const endpoint = {
     devnet: 'http://api.devnet.solana.com',
     testnet: 'http://api.testnet.solana.com',
     'mainnet-beta': 'http://api.mainnet-beta.solana.com',
+    localhost: 'http://localhost',
   },
   https: {
     devnet: 'https://api.devnet.solana.com',
     testnet: 'https://api.testnet.solana.com',
     'mainnet-beta': 'https://api.mainnet-beta.solana.com',
+    localhost: 'https://localhost',
   },
 };
 
-export type Cluster = 'devnet' | 'testnet' | 'mainnet-beta';
+export type Cluster = 'devnet' | 'testnet' | 'mainnet-beta' | 'localhost';
 
 /**
  * Retrieves the RPC API URL for the specified cluster
  */
-export function clusterApiUrl(cluster?: Cluster, tls?: boolean): string {
+export function clusterApiUrl(cluster?: Cluster, tls?: boolean, port: string = '8899'): string {
   const key = tls === false ? 'http' : 'https';
 
   if (!cluster) {
     return endpoint[key]['devnet'];
   }
 
+  if (cluster === 'localhost') {
+    return endpoint[key]['localhost'] + `:${port}`;
+  }
+
   const url = endpoint[key][cluster];
   if (!url) {
     throw new Error(`Unknown ${key} cluster: ${cluster}`);

web3.js/test/cluster.test.ts

@@ -1,6 +1,6 @@
-import {expect} from 'chai';
+import { expect } from 'chai';
 
-import {clusterApiUrl} from '../src/util/cluster';
+import { clusterApiUrl } from '../src/util/cluster';
 
 describe('Cluster Util', () => {
   it('invalid', () => {
@@ -19,4 +19,11 @@ describe('Cluster Util', () => {
       'http://api.devnet.solana.com',
     );
   });
+
+  it('localhost', () => {
+    expect(clusterApiUrl('localhost')).to.eq('https://localhost:8899');
+    expect(clusterApiUrl('localhost', true)).to.eq('https://localhost:8899');
+    expect(clusterApiUrl('localhost', false)).to.eq('http://localhost:8899');
+    expect(clusterApiUrl('localhost', false, '7777')).to.eq('http://localhost:7777');
+  });
 });