feat(nextls): init options (#58)

Next LS has support for passing configuring the default MIX_ENV and
MIX_TARGET of your project's runtime, and are accepted as init_options

package.json

@@ -61,6 +61,16 @@
             "default": 9000,
             "markdownDescription": "If adapter is `tcp`, use this port to connect to a running server.\n\nYou can start the server with `path/to/nextls --port <port>`."
           },
+          "elixir-tools.nextLS.MIX_ENV": {
+            "type": "string",
+            "default": "dev",
+            "markdownDescription": "The MIX_ENV to use when starting the runtime for your project."
+          },
+          "elixir-tools.nextLS.MIX_TARGET": {
+            "type": "string",
+            "default": "host",
+            "markdownDescription": "The MIX_TARGET to use when starting the runtime for your project."
+          },
           "elixir-tools.nextLS.installationDirectory": {
             "type": "string",
             "default": "~/.cache/elixir-tools/nextls/bin/",

src/extension.ts

@@ -169,6 +169,12 @@ async function activateNextLS(
         throw new Error("boom");
     }
     const clientOptions: LanguageClientOptions = {
+      initializationOptions: {
+        // eslint-disable-next-line @typescript-eslint/naming-convention
+        mix_env: config.get("MIX_ENV"),
+        // eslint-disable-next-line @typescript-eslint/naming-convention
+        mix_target: config.get("MIX_TARGET"),
+      },
       documentSelector: [
         { scheme: "file", language: "elixir" },
         { scheme: "file", language: "surface" },