fix(devkit): do not duplicate dependencies (#10921)

packages/devkit/src/utils/package-json.spec.ts

@@ -75,4 +75,72 @@ describe('addDependenciesToPackageJson', () => {
     });
     expect(installTask).toBeDefined();
   });
+
+  it('should not add dependencies when they exist in devDependencies or vice versa', () => {
+    // ARRANGE
+    writeJson(tree, 'package.json', {
+      dependencies: {
+        '@nrwl/angular': 'latest',
+      },
+      devDependencies: {
+        '@nrwl/next': 'latest',
+      },
+    });
+
+    // ACT
+    const installTask = addDependenciesToPackageJson(
+      tree,
+      {
+        '@nrwl/next': 'next',
+      },
+      {
+        '@nrwl/angular': 'next',
+      }
+    );
+
+    // ASSERT
+    const { dependencies, devDependencies } = readJson(tree, 'package.json');
+    expect(dependencies).toEqual({
+      '@nrwl/angular': 'latest',
+    });
+    expect(devDependencies).toEqual({
+      '@nrwl/next': 'latest',
+    });
+    expect(installTask).toBeDefined();
+  });
+
+  it('should add additional dependencies when they dont exist in devDependencies or vice versa and not update the ones that do exist', () => {
+    // ARRANGE
+    writeJson(tree, 'package.json', {
+      dependencies: {
+        '@nrwl/angular': 'latest',
+      },
+      devDependencies: {
+        '@nrwl/next': 'latest',
+      },
+    });
+
+    // ACT
+    const installTask = addDependenciesToPackageJson(
+      tree,
+      {
+        '@nrwl/next': 'next',
+        '@nrwl/cypress': 'latest',
+      },
+      {
+        '@nrwl/angular': 'next',
+      }
+    );
+
+    // ASSERT
+    const { dependencies, devDependencies } = readJson(tree, 'package.json');
+    expect(dependencies).toEqual({
+      '@nrwl/angular': 'latest',
+      '@nrwl/cypress': 'latest',
+    });
+    expect(devDependencies).toEqual({
+      '@nrwl/next': 'latest',
+    });
+    expect(installTask).toBeDefined();
+  });
 });

packages/devkit/src/utils/package-json.ts

@@ -3,6 +3,19 @@ import { installPackagesTask } from '../tasks/install-packages-task';
 import type { Tree } from 'nx/src/generators/tree';
 import { GeneratorCallback } from 'nx/src/config/misc-interfaces';
 
+function filterExistingDependencies(
+  dependencies: Record<string, string>,
+  existingDependencies: Record<string, string>
+) {
+  if (!existingDependencies) {
+    return dependencies;
+  }
+
+  return Object.keys(dependencies ?? {})
+    .filter((d) => !existingDependencies[d])
+    .reduce((acc, d) => ({ ...acc, [d]: dependencies[d] }), {});
+}
+
 /**
  * Add Dependencies and Dev Dependencies to package.json
  *
@@ -26,18 +39,31 @@ export function addDependenciesToPackageJson(
 ): GeneratorCallback {
   const currentPackageJson = readJson(tree, packageJsonPath);
 
+  const filteredDependencies = filterExistingDependencies(
+    dependencies,
+    currentPackageJson.devDependencies
+  );
+  const filteredDevDependencies = filterExistingDependencies(
+    devDependencies,
+    currentPackageJson.dependencies
+  );
+
   if (
-    requiresAddingOfPackages(currentPackageJson, dependencies, devDependencies)
+    requiresAddingOfPackages(
+      currentPackageJson,
+      filteredDependencies,
+      filteredDevDependencies
+    )
   ) {
     updateJson(tree, packageJsonPath, (json) => {
       json.dependencies = {
         ...(json.dependencies || {}),
-        ...dependencies,
+        ...filteredDependencies,
         ...(json.dependencies || {}),
       };
       json.devDependencies = {
         ...(json.devDependencies || {}),
-        ...devDependencies,
+        ...filteredDevDependencies,
         ...(json.devDependencies || {}),
       };
       json.dependencies = sortObjectByKeys(json.dependencies);