1 files changed, 75 insertions, 0 deletions
diff --git a/packages/turbo-codemod/src/transforms/add-package-manager.ts b/packages/turbo-codemod/src/transforms/add-package-manager.ts
new file mode 100644
index 0000000..bd6581f
--- /dev/null
+++ b/packages/turbo-codemod/src/transforms/add-package-manager.ts
@@ -0,0 +1,75 @@
+import path from "path";
+import fs from "fs-extra";
+
+import getPackageManager from "../utils/getPackageManager";
+import getPackageManagerVersion from "../utils/getPackageManagerVersion";
+import getTransformerHelpers from "../utils/getTransformerHelpers";
+import { TransformerResults } from "../runner";
+import type { TransformerArgs } from "../types";
+
+// transformer details
+const TRANSFORMER = "add-package-manager";
+const DESCRIPTION = "Set the `packageManager` key in root `package.json` file";
+const INTRODUCED_IN = "1.1.0";
+
+export function transformer({
+  root,
+  options,
+}: TransformerArgs): TransformerResults {
+  const { log, runner } = getTransformerHelpers({
+    transformer: TRANSFORMER,
+    rootPath: root,
+    options,
+  });
+
+  log.info(`Set "packageManager" key in root "package.json" file...`);
+  const packageManager = getPackageManager({ directory: root });
+  if (!packageManager) {
+    return runner.abortTransform({
+      reason: `Unable to determine package manager for ${root}`,
+    });
+  }
+
+  // handle workspaces...
+  let version = null;
+  try {
+    version = getPackageManagerVersion(packageManager, root);
+  } catch (err) {
+    return runner.abortTransform({
+      reason: `Unable to determine package manager version for ${root}`,
+    });
+  }
+  const pkgManagerString = `${packageManager}@${version}`;
+  const rootPackageJsonPath = path.join(root, "package.json");
+  const rootPackageJson = fs.readJsonSync(rootPackageJsonPath);
+  const allWorkspaces = [
+    {
+      name: "package.json",
+      path: root,
+      packageJson: {
+        ...rootPackageJson,
+        packageJsonPath: rootPackageJsonPath,
+      },
+    },
+  ];
+
+  for (const workspace of allWorkspaces) {
+    const { packageJsonPath, ...pkgJson } = workspace.packageJson;
+    const newJson = { ...pkgJson, packageManager: pkgManagerString };
+    runner.modifyFile({
+      filePath: packageJsonPath,
+      after: newJson,
+    });
+  }
+
+  return runner.finish();
+}
+
+const transformerMeta = {
+  name: `${TRANSFORMER}: ${DESCRIPTION}`,
+  value: TRANSFORMER,
+  introducedIn: INTRODUCED_IN,
+  transformer,
+};
+
+export default transformerMeta;