Add exec Node API to FlipperLib

Summary: Changelog: Allow flipper plugins to run "exec" Node API on Flipper server.

Reviewed By: mweststrate

Differential Revision: D32881149

fbshipit-source-id: 46486a47ee9824ca68897c19fd86b4afc7f8bf1d

desktop/flipper-server-core/src/commands/NodeApiExec.tsx

@@ -0,0 +1,39 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import {ExecError, FlipperServerCommands} from 'flipper-common';
+import {exec} from 'child_process';
+import assert from 'assert';
+
+export const commandNodeApiExec: FlipperServerCommands['node-api-exec'] =
+  async (command, options) =>
+    new Promise((resolve, reject) =>
+      exec(command, options, (error, stdout, stderr) => {
+        assert(typeof stdout === 'string');
+        assert(typeof stderr === 'string');
+        if (error) {
+          const wrappedError: ExecError = {
+            message: error.message,
+            stdout,
+            stderr,
+            cmd: error.cmd,
+            killed: error.killed,
+            code: error.code,
+            stack: error.stack,
+          };
+          reject(wrappedError);
+          return;
+        }
+
+        resolve({
+          stdout,
+          stderr,
+        });
+      }),
+    );