# Limit Cyclomatic Complexity (complexity)

Cyclomatic complexity measures the number of linearly independent paths through a program's source code. This rule allows setting a cyclomatic complexity threshold.

```js
function a(x) {
    if (true) {
        return x; // 1st path
    } else if (false) {
        return x+1; // 2nd path
    } else {
        return 4; // 3rd path
    }
}
```

## Rule Details

This rule is aimed at reducing code complexity by capping the amount of cyclomatic complexity allowed in a program. As such, it will warn when the cyclomatic complexity crosses the configured threshold (default is `20`).

Examples of **incorrect** code for a maximum of 2:

```js
/*eslint complexity: ["error", 2]*/

function a(x) {
    if (true) {
        return x;
    } else if (false) {
        return x+1;
    } else {
        return 4; // 3rd path
    }
}
```

Examples of **correct** code for a maximum of 2:

```js
/*eslint complexity: ["error", 2]*/

function a(x) {
    if (true) {
        return x;
    } else {
        return 4;
    }
}
```

## Options

Optionally, you may specify a `max` object property:

```json
"complexity": ["error", 2]
```

is equivalent to

```json
"complexity": ["error", { "max": 2 }]
```

**Deprecated:** the object property `maximum` is deprecated. Please use the property `max` instead.

## When Not To Use It

If you can't determine an appropriate complexity limit for your code, then it's best to disable this rule.

## Further Reading

* [Cyclomatic Complexity](https://en.wikipedia.org/wiki/Cyclomatic_complexity)
* [Complexity Analysis of JavaScript Code](https://ariya.io/2012/12/complexity-analysis-of-javascript-code)
* [More about Complexity in JavaScript](https://craftsmanshipforsoftware.com/2015/05/25/complexity-for-javascript/)
* [About Complexity](https://web.archive.org/web/20160808115119/http://jscomplexity.org/complexity)
* [Discussion about Complexity in ESLint and more links](https://github.com/eslint/eslint/issues/4808#issuecomment-167795140)

## Related Rules

* [max-depth](max-depth.md)
* [max-len](max-len.md)
* [max-lines](max-lines.md)
* [max-lines-per-function](max-lines-per-function.md)
* [max-nested-callbacks](max-nested-callbacks.md)
* [max-params](max-params.md)
* [max-statements](max-statements.md)