feat: enable to put "island" not only in islands directory

[yusukebe]

Related to #45

With this PR, you can put an island component in a directory under /app/routes, not only the /app/islands directory. You should name it with a _ prefix, like _counter.island.tsx.

app
├── client.ts
├── global.d.ts
├── islands
│   └── counter.tsx
├── routes
│   ├── directory
│   │   ├── _counter.island.tsx // <--- You can put it here
│   │   └── index.tsx
│   ├── index.tsx
└── server.ts

It was inefficient to put Islands in /app/islands, which are used only in a certain directory. However, this PR makes it easier to understand the structure by placing Islands in the same directory as the files that use them.

[yusukebe]

Hi @usualoma @bruceharrison1984

Could you review this?

[bruceharrison1984]

LGTM, however why constraint it to islands and routes? Why not just make it src in general? A common pattern i use is to place components into src/components, which wouldn't be possible in this case.

Either way, I think this is a good incremental improvement to the Islands concept.

[yusukebe]

Thanks @bruceharrison1984 !

however why constraint it to islands and routes?

Good question! This is related to the discussion in #45.

At first, I also thought I could just put the island file in /app/islands. However, for DX improvement, I sometimes wanted to place an island in the same directory for the route files.

This is one example:

.
└── app
    ├── islands
    │   └── online-status.tsx
    └── routes
        ├── chats
        │   ├── [id]
        │   │   ├── _chat.island.tsx
        │   │   └── index.tsx
        │   └── index.tsx
        └── index.tsx

I think it would be better to put common islands in /app/islands and specific ones in /app/routes/sub/_foo.island.tsx.

[yusukebe]

@usualoma Any thoughts?

[usualoma]

@yusukebe Thanks. LGTM!

[yusukebe]

Thanks! Merge now.

[liltechnomancer]

Thanks @bruceharrison1984 !

however why constraint it to islands and routes?

Good question! This is related to the discussion in #45.

At first, I also thought I could just put the island file in /app/islands. However, for DX improvement, I sometimes wanted to place an island in the same directory for the route files.

This is one example:

.
└── app
    ├── islands
    │   └── online-status.tsx
    └── routes
        ├── chats
        │   ├── [id]
        │   │   ├── _chat.island.tsx
        │   │   └── index.tsx
        │   └── index.tsx
        └── index.tsx

I think it would be better to put common islands in /app/islands and specific ones in /app/routes/sub/_foo.island.tsx.

I think @bruceharrison1984 was asking why it needs to be in routes (or islands) and it couldn't just include any file with the _component.island.tsx naming convention in app or src.

For example app/comonents/_component.island.tsx or app/auth/_component.island.tsx

My project is ordered by features so it would be nice to do

.
└── app
    └── auth
        ├── components 
        │  ├── _sign-in.island.tsx
        └── index.tsx

I decided to patch this in, I made an issue that includes the patch if you are interested.
#159