There are several ways to structure our JavaScript codes. Modular programming is a best practice for easy maintenance. Let us assume we have a class drawDiagram. In this class I have to implement many functionalities like draw a shape, drag n drop or create a flowchart. While drawing several shapes they have their own properties. To store all their property related programs here I created a separate js file with the name shproperty.js. In this file I created a class shProperty. Passing shape as a parameter. Depending upon the shape (rectangle, ellipse or circle) I can access the shape properties in my class.
Modular Programming Technique
Modular programming is a software design technique that emphasizes breaking down a program into independent, interchangeable components called modules. Each module is designed to perform a specific function and can be developed, tested, and maintained separately. This approach enhances code readability, reusability, and scalability while simplifying debugging and collaboration among developers.
Key Principles of Modular Programming
1. Single Responsibility Principle (SRP) Each module should have a single, well-defined responsibility. This ensures that changes to one part of the system do not inadvertently affect unrelated components.
2. Encapsulation Modules should hide their internal workings and expose only necessary interfaces. This prevents unintended modifications and makes the system more secure and easier to debug.
3. Loose Coupling Modules should depend as little as possible on one another. This reduces the risk of cascading failures when one module is modified.
4. High Cohesion All elements within a module should be closely related to its primary function. This ensures that modules remain focused and efficient.
As shProperty is a function it returns “exports”. Exports is an array. It holds properties & methods those need to access from an another class. Simply declaring a function propertyCalculation() is only accessible to the internals of the class. To create an external function like getProperty() & setProperty() you have to add this function to exports array.
Function init() is the part where you can initialize your class requirements. Before return the exports array call init() for execution. Refer to Object Oriented Programming (OOP) while declaring a private variable use _ before the variable name. For an example in below sample code I created a private variable _shape. In case it required to access _shape from out-side the class. Use get & set methods.
JavaScript Class Example
var shProperty = function (shape) {
var exports = {};
/* Variables in Global Scope */
var _shape = null;
/* Initialization */
function init() {
}
/* Internal Function */
function propertyCalculation() {
}
/* External Function */
exports.setProperty = function () {
};
exports.getProperty = function () {
};
_shape = shape;
init();
return exports;
};
Advantages of Modular Programming
1. Improved Readability Breaking code into smaller, logically organized modules makes it easier to understand. Developers can quickly locate and modify specific functionalities without navigating through a monolithic codebase.
2. Easier Debugging and Maintenance Since modules are self-contained, isolating and fixing bugs becomes simpler. Changes made to one module are less likely to introduce errors in other parts of the program.
3. Enhanced Collaboration Multiple developers can work on different modules simultaneously without conflicts. This accelerates development and allows teams to leverage specialized expertise.
4. Scalability New features can be added by introducing new modules rather than rewriting existing code. This makes the system adaptable to changing requirements.
5. Code Reusability Common functionalities can be packaged into modules and reused across multiple projects, reducing development time and ensuring consistency.
Best Practices for Modular Programming
1. Define Clear Interfaces Ensure that each module has a well-documented interface specifying inputs, outputs, and expected behaviors.
2. Minimize Dependencies Avoid creating modules that rely too heavily on others. Use dependency injection or abstraction layers when necessary.
3. Use Meaningful Naming Conventions Module names should reflect their purpose, making the codebase easier to navigate.
4. Test Modules Independently Unit testing ensures that each module works as intended before integration.
5. Document Thoroughly Maintain clear documentation for each module, including usage examples and potential side effects.
Conclusion
By dividing a system into well-defined modules, developers can enhance readability, reusability, and collaboration while simplifying debugging and future enhancements. As software systems grow in complexity, adopting modular practices becomes increasingly essential for long-term success. Mastering modular programming allows developers to build robust applications that can evolve with changing technological demands.
