Modernizing JavaScript in Dynamics 365: ES6+ Classes vs. Object Prototype Pattern

Using modern JavaScript syntax when defining Organization Requests in D365

In the world of Dynamics 365 Customer Engagement (CE), JavaScript has played a pivotal role in customizing and extending the platform's capabilities. Traditionally, developers used the Sdk object and prototype pattern to define organization requests and their associated functions. However, with the advent of ECMAScript 6 (ES6), JavaScript introduced classes — a feature that offers a more modern, clear, and maintainable approach to structuring code. This article explores the shift from the traditional prototype pattern to using ES6 classes, specifically in the context of Dynamics 365 development, demonstrating the benefits through examples.

The Traditional Approach: Prototype Pattern

Historically, JavaScript developers working with Dynamics 365 would use a namespace object (e.g., Sdk) and attach all their functions to this object's prototype. This pattern was primarily used to manage scope, avoid global namespace pollution, and ensure that methods were reusable across instances.

Using the Prototype Pattern:

var Sdk = Sdk || {};

Sdk.Request = function (msg) {
  this.message = msg;
};

Sdk.Request.prototype.getMetadata = function () {
  return {
    boundParameter: null, // No bound parameter
    parameterTypes: {
      message: {
       typeName: "Edm.String",
       structuralProperty: 1 // Primitive
      }
    },
    operationType: 0, // Action
    operationName: "MyRequest"
  };
};

The Modern Approach: ES6+ Classes

With ES6, classes were introduced to JavaScript, providing a syntactic sugar over the existing prototype-based inheritance but making it much easier to use and understand, especially for developers familiar with OOP languages.

Example using ES6+ Classes:

class Request {
  constructor(msg) {
    this.message = msg;
  }

  getMetadata() {
    return {
      boundParameter: null, // No bound parameter
      parameterTypes: {
        message: {
         typeName: "Edm.String",
         structuralProperty: 1 // Primitive
        }
      },
      operationType: 0, // Action
      operationName: "MyRequest"
    };
  }
}

Advantages of ES6+ Classes vs Legacy Object Prototype Pattern

• Ease of Use: Developers familiar with object-oriented programming will find the class syntax more approachable and logical. It simplifies the definition of constructors and methods, making the code easier to read and maintain.

• Maintainability: As projects scale, maintaining code that uses classes is generally easier. It's simpler to manage changes in request definitions, extend request classes with additional functionality, or debug issues.

• Integration with Modern JavaScript Practices: Classes fit seamlessly into the module systems of modern JavaScript, making it easier to integrate with other parts of a Dynamics 365 project that may be using modern frameworks and libraries.

• Clear Structure: Classes provide a clear and intuitive way to model organization requests. Each request can be encapsulated as a class with its properties and methods (like getMetadata) that handle the specifics of the request.

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Best Practices

When using ES6+ classes in Dynamics 365 CE JavaScript development:

• Embrace New JavaScript Features: Utilize modern JavaScript features such as let/const, arrow functions along with classes to write more concise and secure code.

• Tooling and Transpilation: Use modern tooling environments that support ES6+, such as Babel or TypeScript compilers, to ensure compatibility across all browsers.

The shift from the prototype pattern to ES6+ classes represents a significant step forward in making JavaScript development more accessible and maintainable, particularly in complex applications like Dynamics 365. By adopting modern JavaScript features, developers can write clearer, more robust, and scalable applications, paving the way for easier maintenance and future enhancements.

While the prototype pattern has served well over the years, ES6 classes offer a more structured and powerful way to build applications, making them a preferable choice in today’s development landscape.