ESLint Complexity of Code | eslintcc

eslintcc

ESLint - JavaScript Complexity of Code

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ESLint Complexity of Code

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ESLintCC is a ECMAScript/JavaScript tool that computes complexity of code by using ESLint

ESLint calculates complexity of code, while this tool only collects a report based on his complexity rule messages

Installation and Usage

Requirements, principles of local and global installation and usage are the same as ESLint Installation and Usage

Globally:

$ npm install -g eslintcc
$ eslintcc yourfile.js

Locally:

$ npm install eslintcc
$ ./node_modules/.bin/eslintcc yourfile.js

Integration in JavaScript application:

const { Complexity } = require('eslintcc');

const complexity = new Complexity();
const report = complexity.executeOnFiles(['yourfile.js']);

console.log(JSON.stringify(report, null, '\t'));

Note: ESLintCC ignores all rules, specified in configuration files, and uses to generate a report only complexity rules.

Configuration

ESLintCC uses ESLint along with Its configuration system. You can use configuration comments and files, as described in the configuration for ESLint.

Difference: ESLintCC uses its own settings for complexity rules, so they cannot be overridden through a configuration file. However, you can disable them locally in the file.

Features:

  1. You can configurate parserOptions and parser for specify the JavaScript language support. .eslintrc.json:
{
  "parserOptions": {
    "ecmaVersion": 2017
  }
}
  1. You can disable checks for a specific complexity rule for a file or part of file using a comment:
// For a file
/* eslint max-params: off, max-depth: off */

function myFunc(a, b, c, d, e) {
  //...
}
// For a block
/* eslint-disable max-params */
function myFunc(a, b, c, d, e) {
  //...
}
/* eslint-enable max-params */
function myFunc2(a, b) {
  //...
}
// For a line
/* eslint-disable-next-line max-params */
function myFunc(a, b, c, d, e) {
  //...
}

Complexity ranks

Every function and block will be ranked from A (best complexity score) to F (worst one). This ranks is based on the ranks of complexity of the Python Radon.

Rank Risk

Ranks corresponds to rule complexity scores as follows:

Rules A B C D E F
Logic:            
complexity 1 - 5 6 - 10 11 - 20 21 - 30 31 - 40 41 +
max-depth 1 - 2 3 4 - 5 6 - 7 8 9 +
max-nested-callbacks 1 - 3 4 - 5 6 - 10 11 - 15 16 - 20 21 +
max-params 1 2 3 - 4 5 6 7 +
Raw:            
max-lines 1 - 75 76 - 150 151 - 300 301 - 450 451 - 600 601 +
max-lines-per-function 1 - 13 14 - 25 26 - 50 51 - 75 76 - 100 101 +
max-statements 1 - 3 4 - 5 6 - 10 11 - 15 16 - 20 21 +

Note: For rank “C”, the maximum score, using from the standard score of ESLint rules. See complexity rules. Other rules are calculated relative to the values of the “complexity” rule.

Example formula: [5, 10, 20, 30, 40].map(score => Math.round((score / 20) * defaultRuleScoreLimit))

Command line options

Command line format:

$ eslintcc [options] file.js [file.js] [dir]
Option Type Description
–rules <rules>, -r=<rules> Array of String Rule, or group: all, logic, raw. Default: logic
–format <format>, -f=<format> String Use a specific output format, text or json. Default: text
–average, -a Flag Show the average complexity at the end of output, if used text format
–show-rules, -sr Flag Show rule name and value, if used text format
–greater-than <value>, -gt=<value> String or Number Will show rules more than rank a, b, c, d, e, or rank value
–less-than <value>, -lt=<value> String or Number Will show rules less than rank b, c, d, e, f, or rank value
–no-inline-config, -nlc Flag Disable the use of configuration comments (such as /*eslint-disable*/)
–max-rank <value>, -mr=<value> String or Number Maximum allowed complexity rank for a single message. Default: C
–max-average-rank <value>, -mar=<value> String or Number Maximum allowed complexity rank for average value. Default: B

If the rank value for one message or the average value is higher than the allowed value, the program terminates with error code 1

Command examples

Output as JSON and show rules more than rank E:

$ eslintcc -f=json -gt=e file.js

Use only 2 rules and show rule name:

$ eslintcc --rules complexity --rules max-depth --show-rules file.js