Cost-of-Modules: Unveiling the Hidden Costs of JavaScript Modules

Robert Harris -

In the realm of web development, the optimization of application performance is a perpetual endeavor. A crucial part of this journey involves understanding the costs associated with the JavaScript modules a project employs. The open-source tool, Cost-of-Modules, emerges as a valuable companion for developers seeking insights into the size, load time, and memory usage of JavaScript modules.

Let's delve into the core features and functionalities offered by Cost-of-Modules:

  1. Module Size Calculation:
    • Get a clear picture of the space your modules occupy with precise size calculations.
// JavaScript
import costOfModules from "cost-of-modules";

const modules = [
  "https://unpkg.com/vue@3.2.31/dist/vue.min.js",
  "https://unpkg.com/vue-router@4.0.12/dist/vue-router.min.js",
  "https://unpkg.com/axios@0.21.1/dist/axios.min.js",
];

const size = costOfModules(modules);

console.log(size); // 10.46 KB
  1. Load Time Measurement:
    • Uncover the load time of your modules, a crucial metric for user experience and performance optimization.
// JavaScript
const loadTime = costOfModules(modules, {
  measureLoadTime: true,
});

console.log(loadTime); // 500 ms
  1. Memory Usage Assessment:
    • Gauge the memory footprint of your modules to ensure smooth runtime operation.
// JavaScript
const memoryUsage = costOfModules(modules, {
  measureMemoryUsage: true,
});

console.log(memoryUsage); // 10 MB

Getting started with Cost-of-Modules is a breeze. Install the tool, import the costOfModules module, and invoke the costOfModules() method with the URL list of your modules. Developed using Node.js, this utility is readily available for installation via npm.

For developers seeking a more tailored approach, Cost-of-Modules provides the flexibility to define custom calculation methods.

// JavaScript
const size = costOfModules(modules, {
  sizeCalculator: (module) => {
    // Custom method to calculate module size
    return module.size;
  },
});

console.log(size); // 10.46 KB