1 files changed, 45 insertions, 0 deletions

diff --git a/packages/turbo-codemod/src/commands/migrate/steps/getCurrentVersion.ts b/packages/turbo-codemod/src/commands/migrate/steps/getCurrentVersion.ts
new file mode 100644
index 0000000..3644f8b
--- /dev/null
+++ b/packages/turbo-codemod/src/commands/migrate/steps/getCurrentVersion.ts
@@ -0,0 +1,45 @@
+import path from "path";
+import { existsSync } from "fs-extra";
+
+import getPackageManager from "../../../utils/getPackageManager";
+import { exec } from "../utils";
+import type { MigrateCommandOptions } from "../types";
+
+function getCurrentVersion(
+  directory: string,
+  opts: MigrateCommandOptions
+): string | undefined {
+  const { from } = opts;
+  if (from) {
+    return from;
+  }
+
+  // try global first
+  const turboVersionFromGlobal = exec(`turbo --version`, { cwd: directory });
+
+  if (turboVersionFromGlobal) {
+    return turboVersionFromGlobal;
+  }
+
+  // try to use the package manager to find the version
+  const packageManager = getPackageManager({ directory });
+  if (packageManager) {
+    if (packageManager === "yarn") {
+      return exec(`yarn turbo --version`, { cwd: directory });
+    }
+    if (packageManager === "pnpm") {
+      return exec(`pnpm turbo --version`, { cwd: directory });
+    } else {
+      // this doesn't work for npm, so manually build the binary path
+      const turboBin = path.join(directory, "node_modules", ".bin", "turbo");
+      if (existsSync(turboBin)) {
+        return exec(`${turboBin} --version`, { cwd: directory });
+      }
+    }
+  }
+
+  // unable to determine local version,
+  return undefined;
+}
+
+export default getCurrentVersion;