TypeScript apphost: withEndpoint/withHttpEndpoint lacks callback overload to modify existing endpoints

[DamianEdwards]

Summary

The C# Aspire hosting API provides a callback overload for WithEndpoint that allows modifying an existing endpoint by name (e.g. to change the port of an auto-created endpoint). The TypeScript apphost SDK does not expose this overload, making it impossible to customize endpoints that are automatically created by resource types like AddViteApp.

Problem

AddViteApp automatically creates an http endpoint. There is no way to modify its port after creation because:

1. Calling withHttpEndpoint({ name: "http", port: 3001 }) fails with: "Endpoint with name 'http' already exists"
2. Creating a new endpoint with a different name (e.g. app) adds a second endpoint but doesn't control the port Vite listens on
3. There is no callback overload like the C# API has: WithEndpoint("http", endpoint => { endpoint.Port = 3001; })

Expected Behavior

The TypeScript SDK should support modifying existing endpoints, either via:

// Option A: Callback overload (matching C# API)
.withEndpoint("http", (endpoint) => {
  endpoint.port = 3001;
  endpoint.isProxied = false;
})

// Option B: Allow withHttpEndpoint to update existing endpoints by name
.withHttpEndpoint({ name: "http", port: 3001, isProxied: false })

Workaround

Currently the only workaround is to drop down to addExecutable and manually configure the command, args, and endpoints, losing the benefits of addViteApp (auto package install, Vite config detection, etc.).

Environment

• Aspire SDK: 13.2.1
• TypeScript apphost

[davidfowl]

Fixed by #16039 — WithEndpoint now updates existing endpoints instead of throwing, so withHttpEndpoint/withHttpsEndpoint can be called again to modify an existing endpoint without needing a callback overload.

[davidfowl]

We should still add the callback method.