Quality metrics for Javascript/Typescript

Installation

npm install @modular-rocks/metrics

or

yarn add @modular-rocks/metrics

Metrics

There are currently 8 metrics:

• Cyclomatic
• Total Cyclomatic Complexity
• Maintainability
• Import Coupling
• Identifier Coupling
• Halstead
• LOC
• LCOM*

*LCOM is not directly adaptable to functional Javascript because LCOM compares identifiers in methods in classes. So this LCOM method is a custom adaption that accounts for modern Javascript usage.

Usage

Each metric accepts an Options argument containing configuration options. Either one of two options are required, code or ast.

code is the code string to parse and evaluate. ast is an already parsed AST.

Examples

Execute the following examples in a node environment (not in a browser).

import { cyclomatic, totalCyclomaticComplexity, loc, halstead, maintainability } from "@modular-rocks/metrics"

const opts = {
  code: `
    function calculateAverage(numbers) {
      if (!Array.isArray(numbers)) {
        return 'Invalid input. Please provide an array of numbers.';
      }

      if (numbers.length === 0) {
        return 'Empty array. Please provide an array with at least one number.';
      }

      let sum = 0;
      for (let i = 0; i < numbers.length; i++) {
        sum += numbers[i];
      }

      const average = sum / numbers.length;
      return average;
    }
  `
}

cyclomatic(opts)
// 7

totalCyclomaticComplexity(opts)
// 4

loc(opts)
// 17 

halstead(opts)
// {
// "bugs": 0.0533612357509481,
// "difficulty": 8.125,
// "effort": 2025.446143672791,
// "length": 49,
// "time": 112.52478575959951,
// "vocabulary": 34,
// "volume": 249.2856792212666,
// }

maintainability(opts)
// 75.59906223945923

import { lcom, identifierCoupling } from "@modular-rocks/metrics"

const opts = {
  code: `
    // Shared variables
    let sharedVariable = 0;

    function incrementSharedVariable() {
      sharedVariable++;
      console.log('Shared Variable:', sharedVariable);
    }

    // Not shared variables
    function multiplyNumbers(a, b) {
      let result = a * b;
      console.log('Result:', result);
    }

    function addNumbers(a, b) {
      let sum = a + b;
      console.log('Sum:', sum);
    }
  `
}

lcom(opts)
// {  "cohesion": 0.5, "lcom": 2.25 }

identifierCoupling(opts)
// 0.25

import { importCoupling } from "@modular-rocks/metrics"

const opts = {
  totalModulesCount: 10,
  code: `
    import ModuleA from 'module-a';
    import { FunctionB } from 'module-b';
  `
}

importCoupling(opts)
// 0.003316749585406302

License

To be licensed, either MIT or Apache 2.0. Lets decide.