From 32b47fcc1e70dcfd645974be98db4d31cc728058 Mon Sep 17 00:00:00 2001
From: madflow <madflow@users.noreply.github.com>
Date: Tue, 9 Sep 2025 20:59:58 +0200
Subject: [PATCH] feat: svelte lsp (#2508)

---
 packages/opencode/src/lsp/language.ts |  1 +
 packages/opencode/src/lsp/server.ts   | 52 +++++++++++++++++++++++++++
 packages/web/src/content/docs/lsp.mdx |  1 +
 3 files changed, 54 insertions(+)

diff --git a/packages/opencode/src/lsp/language.ts b/packages/opencode/src/lsp/language.ts
index ccba0183..2b6e0476 100644
--- a/packages/opencode/src/lsp/language.ts
+++ b/packages/opencode/src/lsp/language.ts
@@ -81,6 +81,7 @@ export const LANGUAGE_EXTENSIONS: Record<string, string> = {
   ".zsh": "shellscript",
   ".ksh": "shellscript",
   ".sql": "sql",
+  ".svelte": "svelte",
   ".swift": "swift",
   ".ts": "typescript",
   ".tsx": "typescriptreact",
diff --git a/packages/opencode/src/lsp/server.ts b/packages/opencode/src/lsp/server.ts
index 07cf3ec5..e4b77be0 100644
--- a/packages/opencode/src/lsp/server.ts
+++ b/packages/opencode/src/lsp/server.ts
@@ -654,4 +654,56 @@ export namespace LSPServer {
       }
     },
   }
+
+  export const Svelte: Info = {
+    id: "svelte",
+    extensions: [".svelte"],
+    root: NearestRoot([
+      "tsconfig.json",
+      "jsconfig.json",
+      "package.json",
+      "pnpm-lock.yaml",
+      "yarn.lock",
+      "bun.lockb",
+      "bun.lock",
+      "vite.config.ts",
+      "vite.config.js",
+      "svelte.config.ts",
+      "svelte.config.js",
+    ]),
+    async spawn(root) {
+      let binary = Bun.which("svelteserver")
+      const args: string[] = []
+      if (!binary) {
+        const js = path.join(Global.Path.bin, "node_modules", "svelte-language-server", "bin", "server.js")
+        if (!(await Bun.file(js).exists())) {
+          if (Flag.OPENCODE_DISABLE_LSP_DOWNLOAD) return
+          await Bun.spawn([BunProc.which(), "install", "svelte-language-server"], {
+            cwd: Global.Path.bin,
+            env: {
+              ...process.env,
+              BUN_BE_BUN: "1",
+            },
+            stdout: "pipe",
+            stderr: "pipe",
+            stdin: "pipe",
+          }).exited
+        }
+        binary = BunProc.which()
+        args.push("run", js)
+      }
+      args.push("--stdio")
+      const proc = spawn(binary, args, {
+        cwd: root,
+        env: {
+          ...process.env,
+          BUN_BE_BUN: "1",
+        },
+      })
+      return {
+        process: proc,
+        initialization: {},
+      }
+    },
+  }
 }
diff --git a/packages/web/src/content/docs/lsp.mdx b/packages/web/src/content/docs/lsp.mdx
index 6a661521..40983702 100644
--- a/packages/web/src/content/docs/lsp.mdx
+++ b/packages/web/src/content/docs/lsp.mdx
@@ -24,6 +24,7 @@ opencode comes with several built-in LSP servers for popular languages:
 | vue        | .vue                                                 | Auto-installs for Vue projects      |
 | rust       | .rs                                                  | `rust-analyzer` command available   |
 | clangd     | .c, .cpp, .cc, .cxx, .c++, .h, .hpp, .hh, .hxx, .h++ | Auto-installs for C/C++ projects    |
+| svelte     | .svelte                                              | Auto-installs for Svelte projects   |
 
 LSP servers are automatically enabled when one of the above file extensions are detected and the requirements are met.