Class Data<P>Abstract

The Data class is an abstract representation of a Data Transfer Object (DTO) designed to safely parse and expose data from various structured sources like FormData, URLSearchParams, or JSON objects.

Developers can extend this class to define specific DTOs that map to incoming structured data, providing a type-safe way to access required fields.

Usage

Data is designed to be subclassed, where the subclass defines properties that extract specific values from the provided Parser. The Parser is responsible for retrieving values from the underlying data source (e.g., FormData, JSON).

The primary goal is to standardize data access and ensure the presence of required fields via the parser. This pattern is particularly useful in handling form submissions (e.g., in Remix actions) by validating the structure of incoming data against the defined DTO.

How It Works

  • Each getter in a subclass uses the provided Parser to extract a specific value from the input.
  • The parser's methods (like getString or getNumber) ensure that the data is present and correctly typed, throwing errors if validation fails.
  • Optional fields should be handled by checking their existence (e.g., using parser.has()) before accessing the value.

Method

toJSON Returns a JSON representation of the DTO, with all defined getter properties.

Example

class LoginData extends Data<FormParser> {
  get username() {
    return this.parser.getString("username"); // Ensures the username is defined and a string
  }

  get password() {
    return this.parser.getString("password"); // Ensures the password is defined and a string
  }
}

let data = new LoginData(new FormParser(formData));
data.username; // Access the username safely
data.password; // Access the password safely

Type Parameters

  • P extends Parser = Parser

    The type of the parser that will be used to parse the data.

Constructors

constructor

Properties

parser

Methods

toJSON

Constructors

constructor

Properties

Protectedparser

parser: P

Methods

toJSON

  • toJSON(): Record<string, unknown>

    Converts the Data object into a plain JSON representation, including all properties defined as getters in the subclass.

    The toJSON method dynamically identifies getter properties in the subclass and collects their values to construct a JSON object. This is particularly useful when you want to serialize the Data object for APIs, logging, or other use cases requiring JSON format.

    Returns Record<string, unknown>

    A plain object representing the Data instance with all getter properties.

    Example

    class LoginData extends Data<FormParser> {
      get username() {
        return this.parser.getString("username");
      }
      get password() {
        return this.parser.getString("password");
      }
    }

    const loginData = new LoginData(new FormParser(formData));
    console.log(JSON.stringify(loginData.toJSON()));
    // Output: { "username": "johndoe", "password": "secret" }

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