check-dependencies.ts

import { createProjectGraphAsync, ProjectGraph, reverse } from '@nx/devkit';
import { Schema } from '../schema';

/**
 * Check whether the project to be removed is depended on by another project
 *
 * Throws an error if the project is in use, unless the `--forceRemove` option is used.
 */
export async function checkDependencies(_, schema: Schema): Promise<void> {
  if (schema.forceRemove) {
    return;
  }

  const graph: ProjectGraph = await createProjectGraphAsync();

  const reverseGraph = reverse(graph);

  const deps = reverseGraph.dependencies[schema.projectName] || [];

  if (deps.length > 0) {
    throw new Error(
      `${
        schema.projectName
      } is still a dependency of the following projects:\n${deps
        .map((x) => x.target)
        .join('\n')}`
    );
  }
}