Tree API Reference

Use this reference for safe file and configuration mutations in generators.

Common Methods

• tree.read(path) reads file contents.
• tree.write(path, content) writes/creates files tracked by dry-run.
• tree.exists(path) checks whether a path is present in the virtual tree.
• tree.delete(path) removes files safely in generator context.

High-Value Devkit Helpers

• generateFiles(tree, src, dest, vars) for template-based generation.
• updateJson(tree, path, updater) for structured JSON mutations.
• readProjectConfiguration(tree, project) and updateProjectConfiguration(...) for project settings.

Example Pattern

import { Tree, updateJson, generateFiles, joinPathFragments } from "@nx/devkit";

export default async function generator(tree: Tree, schema: { name: string }) {
  const root = joinPathFragments("libs", schema.name);
  generateFiles(tree, joinPathFragments(__dirname, "files"), root, { ...schema, tmpl: "" });

  updateJson(tree, "nx.json", (json) => {
    json.generators = json.generators ?? {};
    return json;
  });
}

Safety Notes

• Prefer Tree operations over Node fs in generator runtime.
• Keep updates idempotent where possible.