> ## Documentation Index
> Fetch the complete documentation index at: https://docs-staging-actions-modules-ga.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Unit Test an Action That Uses a Module

> Unit tests for a Post Login action that fetches user roles from an external service through a custom module and sets them as an access token claim, denying access on failure, using Jest, Mocha, and Node.js Test Runner in JavaScript and TypeScript.

## Action

The following Post Login action imports a custom module to fetch the user's roles from an external service and sets them as a custom claim on the access token, denying access if the module call fails.

<Tabs>
  <Tab title="JavaScript">
    ```js title="test-an-action-module.js" theme={null}
    /** @import {Event, PostLoginAPI} from "@auth0/actions/post-login/v3" */

    const { getRoles } = require('actions:my-module');

    const CUSTOM_CLAIM_NAMESPACE = 'https://example.com';

    /**
    * Handler that will be called during the execution of a PostLogin flow.
    *
    * @param {Event} event - Details about the user and the context in which they are logging in.
    * @param {PostLoginAPI} api - Interface whose methods can be used to change the behavior of the login.
    */
    exports.onExecutePostLogin = async (event, api) => {
      try {
        const { roles } = await getRoles();

        api.accessToken.setCustomClaim(`${CUSTOM_CLAIM_NAMESPACE}/roles`, roles);
      } catch (err) {
        api.access.deny(err.message);
      }
    }
    ```

    ```js title="my-module.js" theme={null}
    module.exports = {
      /**
       * Returns the user's roles.
       *
       * @returns {{ roles: string[] }} The roles payload.
       */
      getRoles: async () => {
        const response = await fetch(actions.secrets.EVENT_SINK_URL, {
          method: 'GET',
          headers: {
            'Content-Type': 'application/json',
            'X-API-Key': actions.secrets.EVENT_SINK_API_KEY,
          }
        });

        if (!response.ok) {
          throw new Error(`External service responded with status ${response.status}`);
        }

        return response.json();
      }
    };
    ```
  </Tab>

  <Tab title="TypeScript">
    ```ts title="test-an-action-module.ts" theme={null}
    import type { Event, PostLoginAPI } from '@auth0/actions/post-login/v3';

    const { getRoles } = require('actions:my-module');

    const CUSTOM_CLAIM_NAMESPACE = 'https://example.com';

    /**
    * Handler that will be called during the execution of a PostLogin flow.
    *
    * @param {Event} event - Details about the user and the context in which they are logging in.
    * @param {PostLoginAPI} api - Interface whose methods can be used to change the behavior of the login.
    */
    exports.onExecutePostLogin = async (event: Event, api: PostLoginAPI) => {
      try {
        const { roles } = await getRoles();

        api.accessToken.setCustomClaim(`${CUSTOM_CLAIM_NAMESPACE}/roles`, roles);
      } catch (err) {
        api.access.deny((err as Error).message);
      }
    };

    ```

    ```ts title="my-module.ts" theme={null}
    /**
     * Returns the user's roles.
     *
     * @returns The roles payload.
     */
    exports.getRoles = async (): Promise<{ roles: string[] }> => {
      const response = await fetch(actions.secrets.EVENT_SINK_URL, {
        method: 'GET',
        headers: {
          'Content-Type': 'application/json',
          'X-API-Key': actions.secrets.EVENT_SINK_API_KEY,
        },
      });

      if (!response.ok) {
        throw new Error(`External service responded with status ${response.status}`);
      }

      return response.json();
    };

    ```
  </Tab>
</Tabs>

## Unit Test

The unit tests load the action alongside the custom module and mock `fetch` to verify roles are set on success, and that access is denied when the external service returns an error status or the request fails with a network error.

<AccordionGroup>
  <Accordion title="Jest">
    <Tabs>
      <Tab title="JavaScript">
        ```js title="test-an-action-module.spec.js" theme={null}
        const { getDefaultArguments, loadAction } = require('@auth0/actions/post-login/v3/test');
        const path = require('path');

        const DIRNAME = path.dirname('../../../');
        const ACTION_PATH = path.resolve(DIRNAME, './src/test-an-action-module.js');

        const CUSTOM_CLAIM_NAMESPACE = 'https://example.com';

        describe('onExecutePostLogin', () => {
          let loader;
          let event;
          let api;

          beforeEach(async () => {
            [event, api] = getDefaultArguments();
          });

          afterEach(() => {
              jest.resetAllMocks();
          });

          it('uses a module to get roles and set them on the access token', async () => {
            loader = await loadAction(ACTION_PATH, [
              { name: 'my-module', filename: path.resolve(DIRNAME, './src/my-module.js') }],
            );

            jest.spyOn(api.accessToken, 'setCustomClaim');

            jest.spyOn(global, 'fetch').mockResolvedValueOnce({
              ok: true,
              status: 200,
              json: async () => ({ roles: ['admin'] }),
            });

            await loader.execute('onExecutePostLogin', event, api);

            expect(global.fetch).toHaveBeenCalled();
            expect(api.accessToken.setCustomClaim).toHaveBeenCalledWith(`${CUSTOM_CLAIM_NAMESPACE}/roles`, ['admin']);
          });

          it('denies access when the external service responds with an error', async () => {
            loader = await loadAction(ACTION_PATH, [
              { name: 'my-module', filename: path.resolve(DIRNAME, './src/my-module.js') }],
            );

            jest.spyOn(api.access, 'deny');

            jest.spyOn(global, 'fetch').mockResolvedValueOnce({
              ok: false,
              status: 500,
            });

            await loader.execute('onExecutePostLogin', event, api);

            expect(global.fetch).toHaveBeenCalled();
            expect(api.access.deny).toHaveBeenCalledWith('External service responded with status 500');
          });

          it('denies access when fetching roles fails with a network error', async () => {
            loader = await loadAction(ACTION_PATH, [
              { name: 'my-module', filename: path.resolve(DIRNAME, './src/my-module.js') }],
            );

            jest.spyOn(api.access, 'deny');

            jest.spyOn(global, 'fetch').mockRejectedValueOnce(new Error('Network error'));

            await loader.execute('onExecutePostLogin', event, api);

            expect(global.fetch).toHaveBeenCalled();
            expect(api.access.deny).toHaveBeenCalledWith('Network error');
          });
        });

        ```

        ```json title="package.json" theme={null}
        {
          "name": "actions-npm-example-js-jest",
          "version": "1.0.0",
          "description": "",
          "license": "ISC",
          "author": "",
          "type": "commonjs",
          "main": "module-usage.js",
          "scripts": {
            "test": "jest"
          },
          "devDependencies": {
            "@auth0/actions": "^0.32.0",
            "jest": "^30.4.2"
          },
          "jest": {
            "testEnvironment": "node"
          }
        }

        ```

        ```json title="jsconfig.json" theme={null}
        {
          "compilerOptions": {
            "target": "ES2020",
            "module": "commonjs",
            "checkJs": false,
            "baseUrl": ".",
            "paths": {
              "actions:*": [
                "src/*"
              ]
            }
          },
          "include": [
            "src/**/*.js"
          ]
        }

        ```
      </Tab>

      <Tab title="TypeScript">
        ```ts title="test-an-action-module.test.ts" theme={null}
        const { getDefaultArguments, loadAction } = require('@auth0/actions/post-login/v3/test');
        const path = require('path');
        const { compileActionModules } = require('./test-utils/load-compiled-action');

        const DIRNAME = path.dirname('../../../');
        const ACTION_PATH = path.resolve(DIRNAME, './src/test-an-action-module.ts');
        const MODULE_PATH = path.resolve(DIRNAME, './src/my-module.ts');

        const CUSTOM_CLAIM_NAMESPACE = 'https://example.com';

        describe('onExecutePostLogin', () => {
          let loader: any;
          let event: any;
          let api: any;

          beforeEach(async () => {
            [event, api] = getDefaultArguments();
          });

          afterEach(() => {
            jest.resetAllMocks();
          });

          it('uses a module to get roles and set them on the access token', async () => {
            const { compiledActionPath, compiledModules } = compileActionModules(ACTION_PATH, [
              { name: 'my-module', filename: MODULE_PATH },
            ]);
            loader = await loadAction(compiledActionPath, compiledModules);

            jest.spyOn(api.accessToken, 'setCustomClaim');

            jest.spyOn(global, 'fetch').mockResolvedValueOnce({
              ok: true,
              status: 200,
              json: async () => ({ roles: ['admin'] }),
            } as any);

            await loader.execute('onExecutePostLogin', event, api);

            expect(global.fetch).toHaveBeenCalled();
            expect(api.accessToken.setCustomClaim).toHaveBeenCalledWith(`${CUSTOM_CLAIM_NAMESPACE}/roles`, ['admin']);
          });

          it('denies access when the external service responds with an error', async () => {
            const { compiledActionPath, compiledModules } = compileActionModules(ACTION_PATH, [
              { name: 'my-module', filename: MODULE_PATH },
            ]);
            loader = await loadAction(compiledActionPath, compiledModules);

            jest.spyOn(api.access, 'deny');

            jest.spyOn(global, 'fetch').mockResolvedValueOnce({
              ok: false,
              status: 500,
            } as any);

            await loader.execute('onExecutePostLogin', event, api);

            expect(global.fetch).toHaveBeenCalled();
            expect(api.access.deny).toHaveBeenCalledWith('External service responded with status 500');
          });

          it('denies access when fetching roles fails with a network error', async () => {
            const { compiledActionPath, compiledModules } = compileActionModules(ACTION_PATH, [
              { name: 'my-module', filename: MODULE_PATH },
            ]);
            loader = await loadAction(compiledActionPath, compiledModules);

            jest.spyOn(api.access, 'deny');

            jest.spyOn(global, 'fetch').mockRejectedValueOnce(new Error('Network error'));

            await loader.execute('onExecutePostLogin', event, api);

            expect(global.fetch).toHaveBeenCalled();
            expect(api.access.deny).toHaveBeenCalledWith('Network error');
          });
        });

        ```

        ```ts title="load-compiled-action.ts" theme={null}
        import * as fs from 'fs';
        import * as os from 'os';
        import * as path from 'path';
        import * as ts from 'typescript';

        export interface ModuleToCompile {
          name: string;
          filename: string;
        }

        function transpileToTemp(sourcePath: string): string {
          const source = fs.readFileSync(sourcePath, 'utf8');
          const { outputText } = ts.transpileModule(source, {
            compilerOptions: {
              module: ts.ModuleKind.CommonJS,
              target: ts.ScriptTarget.ES2020,
              esModuleInterop: true,
            },
          });

          const tempPath = path.join(
            os.tmpdir(),
            `${path.basename(sourcePath, path.extname(sourcePath))}-${process.pid}-${Date.now()}-${Math.random().toString(36).slice(2)}.js`,
          );
          fs.writeFileSync(tempPath, outputText);
          return tempPath;
        }

        /**
         * loadAction() (from @auth0/actions/*\/test) reads its target file from disk and
         * runs it via vm.compileFunction, so it never goes through ts-node/Vitest's own
         * TS transform. Action sources (and any actions:-registered modules) must be
         * transpiled to plain JS on disk first.
         */
        export function compileActionModules(actionPath: string, modules: ModuleToCompile[] = []) {
          const compiledActionPath = transpileToTemp(actionPath);
          const compiledModules = modules.map((m) => ({
            name: m.name,
            filename: transpileToTemp(m.filename),
          }));

          return { compiledActionPath, compiledModules };
        }

        ```

        ```json title="package.json" theme={null}
        {
          "name": "actions-npm-example-ts-jest",
          "version": "1.0.0",
          "description": "Actions TS",
          "main": "example.ts",
          "scripts": {
            "test": "jest"
          },
          "author": "John Doe",
          "license": "ISC",
          "devDependencies": {
            "@auth0/actions": "^0.32.0",
            "@types/jest": "^29.5.12",
            "@types/node": "22.14.0",
            "jest": "^29.7.0",
            "ts-jest": "^29.1.2",
            "typescript": "^5.9.2"
          }
        }

        ```

        ```js title="jest.config.js" theme={null}
        module.exports = {
          preset: 'ts-jest',
          testEnvironment: 'node',
        };
        ```

        ```json title="tsconfig.json" theme={null}
        {
          "compilerOptions": {
            "target": "ES2020",
            "module": "NodeNext",
            "moduleResolution": "nodenext",
            "esModuleInterop": true,
            "allowSyntheticDefaultImports": true,
            "strict": true,
            "outDir": "dist",
            "declaration": true,
            "sourceMap": true,
            "allowJs": true,
            "checkJs": false,
            "resolveJsonModule": true,
            "skipLibCheck": true,
            "forceConsistentCasingInFileNames": true,
            "isolatedModules": true,
            "noEmit": true,
            "paths": {
              "actions:*": [
                "./src/*"
              ]
            }
          },
          "exclude": [
            "node_modules",
            "dist"
          ],
          "include": [
            "**/*.ts"
          ],
          "ts-node": {
            "transpileOnly": true
          }
        }

        ```
      </Tab>
    </Tabs>
  </Accordion>

  <Accordion title="Mocha">
    <Tabs>
      <Tab title="JavaScript">
        ```js title="test-an-action-module.spec.js" theme={null}
        const sinon = require('sinon');
        const { getDefaultArguments, loadAction } = require('@auth0/actions/post-login/v3/test');
        const path = require('path');

        const DIRNAME = path.dirname('../../../');
        const ACTION_PATH = path.resolve(DIRNAME, './src/test-an-action-module.js');

        const CUSTOM_CLAIM_NAMESPACE = 'https://example.com';

        describe('onExecutePostLogin', () => {
          let loader;
          let event;
          let api;

          beforeEach(async () => {
            [event, api] = getDefaultArguments();
          });

          afterEach(() => {
            sinon.restore();
          });

          it('uses a module to get roles and set them on the access token', async () => {
            loader = await loadAction(ACTION_PATH, [
              { name: 'my-module', filename: path.resolve(DIRNAME, './src/my-module.js') }],
            );

            sinon.spy(api.accessToken, 'setCustomClaim');

            sinon.stub(global, 'fetch').resolves({
              ok: true,
              status: 200,
              json: async () => ({ roles: ['admin'] }),
            });

            await loader.execute('onExecutePostLogin', event, api);

            sinon.assert.called(global.fetch);
            sinon.assert.calledWith(api.accessToken.setCustomClaim, `${CUSTOM_CLAIM_NAMESPACE}/roles`, ['admin']);
          });

          it('denies access when the external service responds with an error', async () => {
            loader = await loadAction(ACTION_PATH, [
              { name: 'my-module', filename: path.resolve(DIRNAME, './src/my-module.js') }],
            );

            sinon.spy(api.access, 'deny');

            sinon.stub(global, 'fetch').resolves({
              ok: false,
              status: 500,
            });

            await loader.execute('onExecutePostLogin', event, api);

            sinon.assert.called(global.fetch);
            sinon.assert.calledWith(api.access.deny, 'External service responded with status 500');
          });

          it('denies access when fetching roles fails with a network error', async () => {
            loader = await loadAction(ACTION_PATH, [
              { name: 'my-module', filename: path.resolve(DIRNAME, './src/my-module.js') }],
            );

            sinon.spy(api.access, 'deny');

            sinon.stub(global, 'fetch').rejects(new Error('Network error'));

            await loader.execute('onExecutePostLogin', event, api);

            sinon.assert.called(global.fetch);
            sinon.assert.calledWith(api.access.deny, 'Network error');
          });
        });

        ```

        ```json title="package.json" theme={null}
        {
          "name": "actions-npm-example-js-mocha",
          "version": "1.0.0",
          "description": "",
          "license": "ISC",
          "author": "",
          "type": "commonjs",
          "main": "module-usage.js",
          "scripts": {
            "test": "mocha"
          },
          "devDependencies": {
            "@auth0/actions": "^0.32.0",
            "chai": "^4.5.0",
            "mocha": "^11.0.0",
            "sinon": "^19.0.0"
          }
        }

        ```

        ```json title=".mocharc.json" theme={null}
        {
          "spec": "src/**/*.spec.js"
        }

        ```

        ```json title="jsconfig.json" theme={null}
        {
          "compilerOptions": {
            "target": "ES2020",
            "module": "commonjs",
            "checkJs": false,
            "baseUrl": ".",
            "paths": {
              "actions:*": [
                "src/*"
              ]
            }
          },
          "include": [
            "src/**/*.js"
          ]
        }

        ```
      </Tab>

      <Tab title="TypeScript">
        ```ts title="test-an-action-module.test.ts" theme={null}
        import * as path from 'path';
        import sinon from 'sinon';
        import { compileActionModules } from './test-utils/load-compiled-action';

        const { getDefaultArguments, loadAction } = require('@auth0/actions/post-login/v3/test');

        const DIRNAME = path.dirname('../../../');
        const ACTION_PATH = path.resolve(DIRNAME, './src/test-an-action-module.ts');
        const MY_MODULE_PATH = path.resolve(DIRNAME, './src/my-module.ts');
        const CUSTOM_CLAIM_NAMESPACE = 'https://example.com';

        describe('onExecutePostLogin', () => {
          let loader: any;
          let event: any;
          let api: any;

          beforeEach(async () => {
            [event, api] = getDefaultArguments();
          });

          afterEach(() => {
            sinon.restore();
          });

          it('uses a module to get roles and set them on the access token', async () => {
            const { compiledActionPath, compiledModules } = compileActionModules(ACTION_PATH, [
              { name: 'my-module', filename: MY_MODULE_PATH },
            ]);
            loader = await loadAction(compiledActionPath, compiledModules);

            sinon.spy(api.accessToken, 'setCustomClaim');

            sinon.stub(global, 'fetch').resolves({
              ok: true,
              status: 200,
              json: async () => ({ roles: ['admin'] }),
            } as any);

            await loader.execute('onExecutePostLogin', event, api);

            sinon.assert.called(global.fetch as any);
            sinon.assert.calledWith(api.accessToken.setCustomClaim, `${CUSTOM_CLAIM_NAMESPACE}/roles`, ['admin']);
          });

          it('denies access when the external service responds with an error', async () => {
            const { compiledActionPath, compiledModules } = compileActionModules(ACTION_PATH, [
              { name: 'my-module', filename: MY_MODULE_PATH },
            ]);
            loader = await loadAction(compiledActionPath, compiledModules);

            sinon.spy(api.access, 'deny');

            sinon.stub(global, 'fetch').resolves({
              ok: false,
              status: 500,
            } as any);

            await loader.execute('onExecutePostLogin', event, api);

            sinon.assert.called(global.fetch as any);
            sinon.assert.calledWith(api.access.deny, 'External service responded with status 500');
          });

          it('denies access when fetching roles fails with a network error', async () => {
            const { compiledActionPath, compiledModules } = compileActionModules(ACTION_PATH, [
              { name: 'my-module', filename: MY_MODULE_PATH },
            ]);
            loader = await loadAction(compiledActionPath, compiledModules);

            sinon.spy(api.access, 'deny');

            sinon.stub(global, 'fetch').rejects(new Error('Network error'));

            await loader.execute('onExecutePostLogin', event, api);

            sinon.assert.called(global.fetch as any);
            sinon.assert.calledWith(api.access.deny, 'Network error');
          });
        });

        ```

        ```ts title="load-compiled-action.ts" theme={null}
        import * as fs from 'fs';
        import * as os from 'os';
        import * as path from 'path';
        import * as ts from 'typescript';

        export interface ModuleToCompile {
          name: string;
          filename: string;
        }

        function transpileToTemp(sourcePath: string): string {
          const source = fs.readFileSync(sourcePath, 'utf8');
          const { outputText } = ts.transpileModule(source, {
            compilerOptions: {
              module: ts.ModuleKind.CommonJS,
              target: ts.ScriptTarget.ES2020,
              esModuleInterop: true,
            },
          });

          const tempPath = path.join(
            os.tmpdir(),
            `${path.basename(sourcePath, path.extname(sourcePath))}-${process.pid}-${Date.now()}-${Math.random().toString(36).slice(2)}.js`,
          );
          fs.writeFileSync(tempPath, outputText);
          return tempPath;
        }

        /**
         * loadAction() (from @auth0/actions/*\/test) reads its target file from disk and
         * runs it via vm.compileFunction, so it never goes through ts-node/Vitest's own
         * TS transform. Action sources (and any actions:-registered modules) must be
         * transpiled to plain JS on disk first.
         */
        export function compileActionModules(actionPath: string, modules: ModuleToCompile[] = []) {
          const compiledActionPath = transpileToTemp(actionPath);
          const compiledModules = modules.map((m) => ({
            name: m.name,
            filename: transpileToTemp(m.filename),
          }));

          return { compiledActionPath, compiledModules };
        }

        ```

        ```json title="package.json" theme={null}
        {
          "name": "actions-npm-example-ts-mocha",
          "version": "1.0.0",
          "description": "",
          "license": "ISC",
          "author": "",
          "scripts": {
            "test": "NODE_OPTIONS=--no-experimental-strip-types mocha"
          },
          "devDependencies": {
            "@auth0/actions": "^0.32.0",
            "@types/chai": "^4.3.16",
            "@types/mocha": "^10.0.6",
            "@types/node": "22.14.0",
            "@types/sinon": "^17.0.3",
            "chai": "^4.5.0",
            "mocha": "^11.0.0",
            "sinon": "^19.0.0",
            "ts-node": "^10.9.2",
            "typescript": "^5.9.2"
          }
        }

        ```

        ```json title=".mocharc.json" theme={null}
        {
          "require": "ts-node/register",
          "extension": ["ts"],
          "spec": "src/**/*.test.ts"
        }

        ```

        ```json title="tsconfig.json" theme={null}
        {
          "compilerOptions": {
            "target": "ES2020",
            "module": "NodeNext",
            "moduleResolution": "nodenext",
            "esModuleInterop": true,
            "allowSyntheticDefaultImports": true,
            "strict": true,
            "outDir": "dist",
            "declaration": true,
            "sourceMap": true,
            "allowJs": true,
            "checkJs": false,
            "resolveJsonModule": true,
            "skipLibCheck": true,
            "forceConsistentCasingInFileNames": true,
            "isolatedModules": true,
            "noEmit": true,
            "paths": {
              "actions:*": [
                "./src/*"
              ]
            }
          },
          "exclude": [
            "node_modules",
            "dist"
          ],
          "include": [
            "**/*.ts"
          ],
          "ts-node": {
            "transpileOnly": true
          }
        }

        ```
      </Tab>
    </Tabs>
  </Accordion>

  <Accordion title="Node.js Test Runner">
    <Tabs>
      <Tab title="JavaScript">
        ```js title="test-an-action-module.spec.js" theme={null}
        const assert = require('node:assert');
        const { describe, it, beforeEach, afterEach, mock } = require('node:test');
        const { getDefaultArguments, loadAction } = require('@auth0/actions/post-login/v3/test');
        const path = require('path');

        const DIRNAME = path.dirname('../../../');
        const ACTION_PATH = path.resolve(DIRNAME, './src/test-an-action-module.js');

        const CUSTOM_CLAIM_NAMESPACE = 'https://example.com';

        describe('onExecutePostLogin', () => {
          let loader;
          let event;
          let api;

          beforeEach(async () => {
            [event, api] = getDefaultArguments();
          });

          afterEach(() => {
            mock.reset();
          });

          it('uses a module to get roles and set them on the access token', async () => {
            loader = await loadAction(ACTION_PATH, [
              { name: 'my-module', filename: path.resolve(DIRNAME, './src/my-module.js') }],
            );

            mock.method(api.accessToken, 'setCustomClaim');

            mock.method(global, 'fetch', async () => ({
              ok: true,
              status: 200,
              json: async () => ({ roles: ['admin'] }),
            }));

            await loader.execute('onExecutePostLogin', event, api);

            assert.strictEqual(global.fetch.mock.calls.length, 1);
            assert.deepEqual(api.accessToken.setCustomClaim.mock.calls[0].arguments, [
              `${CUSTOM_CLAIM_NAMESPACE}/roles`,
              ['admin'],
            ]);
          });

          it('denies access when the external service responds with an error', async () => {
            loader = await loadAction(ACTION_PATH, [
              { name: 'my-module', filename: path.resolve(DIRNAME, './src/my-module.js') }],
            );

            mock.method(api.access, 'deny');

            mock.method(global, 'fetch', async () => ({
              ok: false,
              status: 500,
            }));

            await loader.execute('onExecutePostLogin', event, api);

            assert.strictEqual(global.fetch.mock.calls.length, 1);
            assert.deepEqual(api.access.deny.mock.calls[0].arguments, ['External service responded with status 500']);
          });

          it('denies access when fetching roles fails with a network error', async () => {
            loader = await loadAction(ACTION_PATH, [
              { name: 'my-module', filename: path.resolve(DIRNAME, './src/my-module.js') }],
            );

            mock.method(api.access, 'deny');

            mock.method(global, 'fetch', async () => {
              throw new Error('Network error');
            });

            await loader.execute('onExecutePostLogin', event, api);

            assert.strictEqual(global.fetch.mock.calls.length, 1);
            assert.deepEqual(api.access.deny.mock.calls[0].arguments, ['Network error']);
          });
        });

        ```

        ```json title="package.json" theme={null}
        {
          "name": "actions-npm-example-js-node-test",
          "version": "1.0.0",
          "description": "",
          "license": "ISC",
          "author": "",
          "type": "commonjs",
          "main": "module-usage.js",
          "scripts": {
            "test": "node --test src/*.spec.js"
          },
          "devDependencies": {
            "@auth0/actions": "^0.32.0"
          }
        }

        ```

        ```json title="jsconfig.json" theme={null}
        {
          "compilerOptions": {
            "target": "ES2020",
            "module": "commonjs",
            "checkJs": false,
            "baseUrl": ".",
            "paths": {
              "actions:*": [
                "src/*"
              ]
            }
          },
          "include": [
            "src/**/*.js"
          ]
        }

        ```
      </Tab>

      <Tab title="TypeScript">
        ```ts title="test-an-action-module.test.ts" theme={null}
        const assert = require('node:assert');
        const { describe, it, beforeEach, afterEach, mock } = require('node:test');
        const { getDefaultArguments, loadAction } = require('@auth0/actions/post-login/v3/test');
        const path = require('path');
        const { compileActionModules } = require('./test-utils/load-compiled-action.ts');

        const DIRNAME = path.dirname('../../../');
        const ACTION_PATH = path.resolve(DIRNAME, './src/test-an-action-module.ts');
        const MY_MODULE_PATH = path.resolve(DIRNAME, './src/my-module.ts');

        const CUSTOM_CLAIM_NAMESPACE = 'https://example.com';

        describe('onExecutePostLogin', () => {
          let loader;
          let event;
          let api;

          beforeEach(async () => {
            [event, api] = getDefaultArguments();
          });

          afterEach(() => {
            mock.reset();
          });

          it('uses a module to get roles and set them on the access token', async () => {
            const { compiledActionPath, compiledModules } = compileActionModules(ACTION_PATH, [
              { name: 'my-module', filename: MY_MODULE_PATH },
            ]);
            loader = await loadAction(compiledActionPath, compiledModules);

            mock.method(api.accessToken, 'setCustomClaim');

            mock.method(global, 'fetch', async () => ({
              ok: true,
              status: 200,
              json: async () => ({ roles: ['admin'] }),
            }));

            await loader.execute('onExecutePostLogin', event, api);

            assert.strictEqual(global.fetch.mock.calls.length, 1);
            assert.deepEqual(api.accessToken.setCustomClaim.mock.calls[0].arguments, [
              `${CUSTOM_CLAIM_NAMESPACE}/roles`,
              ['admin'],
            ]);
          });

          it('denies access when the external service responds with an error', async () => {
            const { compiledActionPath, compiledModules } = compileActionModules(ACTION_PATH, [
              { name: 'my-module', filename: MY_MODULE_PATH },
            ]);
            loader = await loadAction(compiledActionPath, compiledModules);

            mock.method(api.access, 'deny');

            mock.method(global, 'fetch', async () => ({
              ok: false,
              status: 500,
            }));

            await loader.execute('onExecutePostLogin', event, api);

            assert.strictEqual(global.fetch.mock.calls.length, 1);
            assert.deepEqual(api.access.deny.mock.calls[0].arguments, ['External service responded with status 500']);
          });

          it('denies access when fetching roles fails with a network error', async () => {
            const { compiledActionPath, compiledModules } = compileActionModules(ACTION_PATH, [
              { name: 'my-module', filename: MY_MODULE_PATH },
            ]);
            loader = await loadAction(compiledActionPath, compiledModules);

            mock.method(api.access, 'deny');

            mock.method(global, 'fetch', async () => {
              throw new Error('Network error');
            });

            await loader.execute('onExecutePostLogin', event, api);

            assert.strictEqual(global.fetch.mock.calls.length, 1);
            assert.deepEqual(api.access.deny.mock.calls[0].arguments, ['Network error']);
          });
        });

        ```

        ```ts title="load-compiled-action.ts" theme={null}
        const fs = require('fs');
        const os = require('os');
        const path = require('path');
        const ts = require('typescript');

        interface ModuleToCompile {
          name: string;
          filename: string;
        }

        function transpileToTemp(sourcePath: string): string {
          const source = fs.readFileSync(sourcePath, 'utf8');
          const { outputText } = ts.transpileModule(source, {
            compilerOptions: {
              module: ts.ModuleKind.CommonJS,
              target: ts.ScriptTarget.ES2020,
              esModuleInterop: true,
            },
          });

          const tempPath = path.join(
            os.tmpdir(),
            `${path.basename(sourcePath, path.extname(sourcePath))}-${process.pid}-${Date.now()}-${Math.random().toString(36).slice(2)}.js`,
          );
          fs.writeFileSync(tempPath, outputText);
          return tempPath;
        }

        /**
         * loadAction() (from @auth0/actions/*\/test) reads its target file from disk and
         * runs it via vm.compileFunction, so it never goes through node's native TS type
         * stripping. Action sources (and any actions:-registered modules) must be
         * transpiled to plain JS on disk first.
         */
        exports.compileActionModules = function compileActionModules(actionPath: string, modules: ModuleToCompile[] = []) {
          const compiledActionPath = transpileToTemp(actionPath);
          const compiledModules = modules.map((m: ModuleToCompile) => ({
            name: m.name,
            filename: transpileToTemp(m.filename),
          }));

          return { compiledActionPath, compiledModules };
        };

        ```

        ```json title="package.json" theme={null}
        {
          "name": "actions-npm-example-ts-node-test",
          "version": "1.0.0",
          "description": "",
          "license": "ISC",
          "author": "",
          "scripts": {
            "test": "node --test src/*.test.ts"
          },
          "devDependencies": {
            "@auth0/actions": "^0.32.0",
            "@types/node": "22.14.0",
            "typescript": "^5.9.2"
          }
        }

        ```

        ```json title="tsconfig.json" theme={null}
        {
          "compilerOptions": {
            "target": "ES2020",
            "module": "NodeNext",
            "moduleResolution": "nodenext",
            "esModuleInterop": true,
            "allowSyntheticDefaultImports": true,
            "strict": true,
            "outDir": "dist",
            "declaration": true,
            "sourceMap": true,
            "allowJs": true,
            "checkJs": false,
            "resolveJsonModule": true,
            "skipLibCheck": true,
            "forceConsistentCasingInFileNames": true,
            "isolatedModules": true,
            "noEmit": true,
            "paths": {
              "actions:*": [
                "./src/*"
              ]
            }
          },
          "exclude": [
            "node_modules",
            "dist"
          ],
          "include": [
            "**/*.ts"
          ],
          "ts-node": {
            "transpileOnly": true
          }
        }

        ```
      </Tab>
    </Tabs>
  </Accordion>
</AccordionGroup>