Momentic tests can run arbitrary JavaScript code to craft complex logic and achieve dynamic behavior within steps.

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JavaScript step

The JavaScript steps allows you to execute JavaScript code. Asynchronous code using async and await is supported.

The output of the step is set to the final return value. This value must be serializable (e.g. you cannot return a class or a function).

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{{ }} expressions

Do not use {{}} expressions within JavaScript steps. There is no need to do so since any variables and functions can be referenced directly.

String input fields in every step step can contain JavaScript expressions inside curly brackets. At test runtime, these expressions are evaluated and the templated value is used instead.

For example, the value of a Type step can be set to {{ env.USERNAME }}@gmail.com, which might evaluate to something like johndoe@gmail.com.

You should not include a return statement in these expressions.

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Execution context

By default, all code executes in an isolated Node.js sandbox. This ensures that one test’s code cannot access other users’ data, modify the test environment, or consume excessive resources.

You can also execute the code in the current page’s JavaScript context by turn on the Execute in browser option. You will have access to globals like window, document, and other browser APIs. This is useful for interacting with the page directly, such as manipulating the DOM or accessing browser-specific features.

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Globals

These globals are only available in the Node.js sandbox environment.

In addition to the Node.js built-in libraries, Momentic provides several third-party packages, special utility functions, and global constants to accelerate the testing experience.

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Third-party packages

  • axios: For making HTTP/HTTPS requests. Please see the official documentation for usage and examples.
  • assert: For executing assertions based on variables and constants. Please see the official Node.js documentation for usage and examples.
  • faker: For generating mock data. Please see the official documentation for usage and examples.
  • moment: For creating and manipulating Date objects. Please see the official documentation for usage and examples.
  • createAppAuth: For authenticating with the GitHub API as a GitHub app. Please see the official documentation for usage and examples.
  • Octokit: For interacting with the GitHub API. Using this function may incur additional runtime. Please see the official documentation
  • pg: For interacting with PostgreSQL databases. Please see the official documentation for usage and examples.

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Special utility functions

  • setVariable: For setting a variable in the test context. Read more in Variables.

  • sms: For sending and receiving SMS messages. Read more in SMS.

  • email: For sending and receiving email messages. Read more in Email.

  • ai: For interacting with an LLM to generate text. Read more in Generating text.

  • extractCookiesFromResponse: For extracting cookies from a Response object, which is the type returned from fetch and axios calls. The cookies are returned in a format compatible with Playwright as well as the Load auth state step.

      type CookieSetting = {
    name: string;
    value: string;
    domain: string;
    path: string;
    expires: number;
    httpOnly: boolean;
    secure: boolean;
    sameSite: "Strict" | "Lax" | "None";
  };

  async function extractCookiesFromResponse(
    response: Response,
  ): Promise<CookieSetting[]>;