ESLintCC is a ECMAScript/JavaScript tool that computes complexity of code by using ESLint
npm install eslintcc[ESLintCC][npm_url] is a ECMAScript/JavaScript/TypeScript tool
that computes complexity of code by using [ESLint][eslint_npm]
> ESLint calculates complexity of code,
> while this tool only collects a report based on his [complexity rule messages][eslint_rule]
> Requirements, principles of local and global installation and usage
> are the same as [ESLint Installation and Usage][eslint_usage]
Globally:
$ npm install -g eslintcc
$ eslintcc yourfile.js
Locally:
$ npm install eslintcc
$ ./node_modules/.bin/eslintcc yourfile.js
NPX (you can do it without installing):
$ npx eslintcc yourfile.js
Integration in JavaScript application (see more...):
``js
const { Complexity } = require('eslintcc');
const complexity = new Complexity();
const report = await complexity.lintFiles(['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][eslint_rule].
ESLintCC uses ESLint along with [Its configuration system][eslint_config].
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][eslint_parser_options]
or [parser][eslint_parser] for specify the JavaScript language support. .eslintrc.json:
`json`
{
"parserOptions": {
"ecmaVersion": 2021,
"sourceType": "module"
}
}
`json`
{
"parser": "@typescript-eslint/parser"
}
2. You can disable checks for a specific complexity rule for a file or part of file
[using a comment][eslint_disabling_comments]:
`js
// For a file
/ eslint max-params: off, max-depth: off /
function myFunc(a, b, c, d, e) {
//...
}
`
`js`
// For a block
/ eslint-disable max-params /
function myFunc(a, b, c, d, e) {
//...
}
/ eslint-enable max-params /
function myFunc2(a, b) {
//...
}
`js`
// For a line
/ eslint-disable-next-line max-params /
function myFunc(a, b, c, d, e) {
//...
}
Examples of [ESLint Parser][eslint_parser] configuration
Using Babel you can support experimental syntax.
For example private fields and methods for classes.
> See package @babel/eslint-parser
package.json
`json`
{
"devDependencies": {
"@babel/eslint-parser": "latest",
"@babel/plugin-transform-class-properties": "latest",
"@babel/plugin-transform-private-methods": "latest"
}
}
.eslintrc.json
`json`
{
"parser": "@babel/eslint-parser",
"parserOptions": {
"sourceType": "module",
"babelOptions": {
"configFile": "./babel.config.json"
}
}
}
.babel.config.json
`json`
{
"plugins": [
"@babel/plugin-transform-class-properties",
"@babel/plugin-transform-private-methods"
]
}
> See package @typescript-eslint/parser
This parser is used you can add a code complexity score to your TypeScript project.
In this case, the same standard ESLint rules are used for calculating complexity,
described in "Complexity ranks" section.
package.json
`json`
{
"devDependencies": {
"typescript": "latest",
"@typescript-eslint/parser": "latest",
"@typescript-eslint/eslint-plugin": "latest"
}
}
.eslintrc.json
`json`
{
"overrides": [
{
"files": [
"*.ts"
],
"parser": "@typescript-eslint/parser",
"plugins": [
"@typescript-eslint"
],
"extends": [
"eslint:recommended",
"plugin:@typescript-eslint/recommended"
]
}
]
}
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][radon_cc_rank].
Rank Risk
* A low - simple block
* B low - well structured and stable block
* C moderate - slightly complex block
* D more than moderate - more complex block
* E high - complex block, alarming
* F very high - error-prone, unstable block
Ranks corresponds to rule complexity scores as follows:
| Rules | A | B | C | D | E | F |
| ----------------------------------------------------------- | ------ | -------- | --------- | --------- | --------- | ----- |
| Logic: | | | | | | |
| [complexity][eslint_rule] | 1 - 5 | 6 - 10 | 11 - 20 | 21 - 30 | 31 - 40 | 41 + |
| [max-depth][eslint_max_depth] | 1 - 2 | 3 | 4 - 5 | 6 - 7 | 8 | 9 + |
| [max-nested-callbacks][eslint_max_nested_callbacks] | 1 - 3 | 4 - 5 | 6 - 10 | 11 - 15 | 16 - 20 | 21 + |
| [max-params][eslint_max_params] | 1 | 2 | 3 - 4 | 5 | 6 | 7 + |
| Raw: | | | | | | |
| [max-lines][eslint_max_lines] | 1 - 75 | 76 - 150 | 151 - 300 | 301 - 450 | 451 - 600 | 601 + |
| [max-lines-per-function][eslint_max_lines_per_function] | 1 - 13 | 14 - 25 | 26 - 50 | 51 - 75 | 76 - 100 | 101 + |
| [max-statements][eslint_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][eslint_rule].
> 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 format:
$ eslintcc [options] file.js [file.js] [dir]
| Option | Type | Description |
| ---------------------------------------------- | ---------------- | ------------------------------------------------------------------------ |
| --rules \
| --format \
| --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 \
| --less-than \
| --no-inline-config, -nlc | Flag | Disable the use of configuration comments (such as /eslint-disable/) |
| --max-rank \
| --max-average-rank \
> If the rank value for one message or the average value is higher than the allowed value, the program terminates with error code 1
Output as JSON and show rules more than rank E:
$ npx eslintcc -f=json -gt=e file.js
Use only 2 rules and show rule name:
$ npx eslintcc --rules complexity --rules max-depth --show-rules file.js
> Based on the test files from the directory:
> ./test/src/
$ npx eslintcc --show-rules ./test/src/complexity__max_rank.js
B test/src/complexity__max_rank.js
D 3:0 function MyFunc (max-params = 4)
A 9:0 function MyFunc1 (max-params = 1)
A 15:0 function MyFunc2 (max-params = 1)
A 21:0 function MyFunc3 (max-params = 1)
B 27:0 function myFunc4 (max-params = 2)
A 28:2 function myFunc4, IfStatement (28:2-32:3) (max-depth = 1)
A 29:7 function myFunc4, arrow function (29:7-31:5) (max-nested-callbacks = 1)
Error: Complexity of code above maximum allowable rank C (3), messages - 1
$ npx eslintcc --format json ./test/src/complexity__max_average_rank.js
{"files":[{"file":"/development/github/eslintcc/test/src/complexity__max_average_rank.js","messages":[{"loc":{"start":{"line":3,"column":0},"end":{"line":5,"column":1}},"type":"function","name":"function MyFunc","rules":{"max-params":{"value":3,"rank":3,"label":"C"},"complexity":{"value":1,"rank":0.2,"label":"A"}},"maxRule":"max-params"}],"average":{"rank":3,"label":"C"}}],"average":{"rank":3,"label":"C"},"ranks":{"A":0,"B":0,"C":1,"D":0,"E":0,"F":0},"errors":{"maxRank":0,"maxAverageRank":true}}
$ npx eslintcc --show-rules ./test/src/custom_parser/typescript-eslint-parser.ts
A test/src/custom_parser/typescript-eslint-parser.ts
A 6:7 function test (max-params = 1)
A 7:4 function test, IfStatement (7:4-11:5) (max-depth = 1)
While ESLintСС is designed to be run on the command line,
it's possible to use ESLintСС programmatically through the Node.js API.
The purpose of the Node.js API is to allow plugin and tool authors to use the ESLintСС functionality directly,
without going through the command line interface.
Is a main class for use in Node.js applications.
#### Example
`js
const { Complexity } = require('eslintcc');
const complexity = new Complexity({
rules: 'logic',
eslintOptions: {
useEslintrc: false,
overrideConfig: {
parser: '@typescript-eslint/parser',
plugins: ['@typescript-eslint'],
extends: ['eslint:recommended', 'plugin:@typescript-eslint/recommended']
}
}
});
const report = await complexity.lintFiles(['yourfile.ts']);
console.log(JSON.stringify(report, null, '\t'));
`
#### new Complexity(options)
Class options equivalent to the command line (see Command line options):
options.rules, Default: 'logic'*
options.greaterThan, Default: undefined*
options.lessThan, Default: undefined*
options.noInlineConfig, Default: false*
options.maxRank, Default: 'C'*
options.maxAverageRank, Default: 'B'*
Additional options available in API mode:
options.ranks, Default: null* -
Allows you to set an arbitrary comparison of ranks and max counters of indicators of the corresponding rules.
Example:
`js`
const complexity = new Complexity({
ranks: {
'complexity': { A: 5, B: 10, C: 20, D: 30, E: 40, F: Infinity }
'max-depth': { A: 2, B: 3, C: 4, D: 6, E: 8, F: Infinity}
}
})
options.eslintOptions, Default: {}* -
This option allows you to configure the internal ESLint class.
It's allows you to set additional options described in the documentation:
ESLint: Node.js API
#### complexity.lintFiles(patterns)
This method lints the files that match the glob patterns and then returns the results.
Parameters
patterns (string | string\[])* -
The lint target files. This can contain any of file paths, directory paths, and glob patterns.
Return Value
Promise\
The promise that will be fulfilled with an ComplexityResult object.
Example:
`js``
{
'average': { 'rank': 0.2, 'label': 'A' },
'errors': {
'maxAverageRank': false,
'maxRank': 0
},
'ranks': {
'A': 1,
'B': 0,
'C': 0,
'D': 0,
'E': 0,
'F': 0
},
'files': [{
'average': { 'rank': 0.2, 'label': 'A' },
'file': ...absolute path to file...,
'messages': [{
'type': 'function',
'loc': { 'start': { 'line': 3, 'column': 0 }, 'end': { 'line': 5, 'column': 1 } },
'name': 'function myFunc',
'rules': { 'complexity': { 'value': 1, 'rank': 0.2, 'label': 'A' } },
'maxRule': 'complexity'
}]
}]
}
[npm_img]: https://img.shields.io/npm/v/eslintcc.svg
[npm_url]: https://www.npmjs.com/package/eslintcc
[build_img]: https://github.com/eslintcc/eslintcc/actions/workflows/main.yml/badge.svg?branch=main
[build_url]: https://github.com/eslintcc/eslintcc/actions/workflows/main.yml?query=branch:main
[eslint_npm]: https://www.npmjs.com/package/eslint
[eslint_rule]: https://eslint.org/docs/rules/complexity
[eslint_max_depth]: https://eslint.org/docs/rules/max-depth
[eslint_max_lines]: https://eslint.org/docs/rules/max-lines
[eslint_max_lines_per_function]: https://eslint.org/docs/rules/max-lines-per-function
[eslint_max_nested_callbacks]: https://eslint.org/docs/rules/max-nested-callbacks
[eslint_max_params]: https://eslint.org/docs/rules/max-params
[eslint_max_statements]: https://eslint.org/docs/rules/max-statements
[eslint_usage]: https://github.com/eslint/eslint#installation-and-usage
[eslint_config]: https://eslint.org/docs/user-guide/configuring/
[eslint_parser_options]: https://eslint.org/docs/user-guide/configuring/language-options#specifying-parser-options
[eslint_parser]: https://eslint.org/docs/user-guide/configuring/plugins#specifying-parser
[eslint_disabling_comments]: https://eslint.org/docs/user-guide/configuring/rules#disabling-rules
[radon_cc_rank]: https://radon.readthedocs.io/en/latest/api.html#radon.complexity.cc_rank