Why Non‑Modular JavaScript Is Painful and How CMD Solves It

Pain of Non‑Modular Development

When JavaScript code is written without a modular structure, developers quickly encounter naming conflicts and complex file dependencies. For example, a shared utils.js file may define an each function, but another developer might create a different each in a.js, causing collisions that require manual renaming and coordination.

File dependencies become fragile as well. If dialog.js relies on utils.js, every script that uses dialog.js must also include utils.js in the correct order, leading to missing‑script errors and a proliferation of <script> tags.

Benefits of Modular Development

Modern JavaScript module standards (such as CMD, AMD, CommonJS, or ES6 modules) eliminate these problems. Each file becomes a self‑contained module that explicitly declares its dependencies, so naming conflicts disappear and the load order is managed automatically.

CMD Modular Development Example

The following example shows a simple project organized with the CMD specification.

// Directory structure
- js
  - common
    - utils.js
  - a.js

// utils.js (module definition)
define(function(require, exports) {
    // Export the each method
    exports.each = function() { /* implementation */ };
});

// a.js (module that uses utils)
define(function(require, exports) {
    // Import utils module
    var utils = require('common/utils');
    utils.each();

    // Export its own each method
    exports.each = function() { /* implementation */ };
});

CMD introduces three key keywords:

define – declares a module.

require – imports other modules.

exports – exposes the module’s public API.

By following this pattern, developers only need to focus on the functionality of the current module, while the module loader handles dependency resolution and avoids the pitfalls of the non‑modular approach.