/
complexity.js
192 lines (166 loc) · 6.64 KB
/
complexity.js
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/**
* @fileoverview Counts the cyclomatic complexity of each function of the script. See http://en.wikipedia.org/wiki/Cyclomatic_complexity.
* Counts the number of if, conditional, for, while, try, switch/case,
* @author Patrick Brosset
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("./utils/ast-utils");
const { upperCaseFirst } = require("../shared/string-utils");
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
meta: {
type: "suggestion",
docs: {
description: "enforce a maximum cyclomatic complexity allowed in a program",
category: "Best Practices",
recommended: false,
url: "https://eslint.org/docs/rules/complexity"
},
schema: [
{
oneOf: [
{
type: "integer",
minimum: 0
},
{
type: "object",
properties: {
maximum: {
type: "integer",
minimum: 0
},
max: {
type: "integer",
minimum: 0
}
},
additionalProperties: false
}
]
}
],
messages: {
complex: "{{name}} has a complexity of {{complexity}}. Maximum allowed is {{max}}."
}
},
create(context) {
const option = context.options[0];
let THRESHOLD = 20;
if (
typeof option === "object" &&
(Object.prototype.hasOwnProperty.call(option, "maximum") || Object.prototype.hasOwnProperty.call(option, "max"))
) {
THRESHOLD = option.maximum || option.max;
} else if (typeof option === "number") {
THRESHOLD = option;
}
//--------------------------------------------------------------------------
// Helpers
//--------------------------------------------------------------------------
// Using a stack to store complexity (handling nested functions)
const fns = [];
/**
* When parsing a new function, store it in our function stack
* @returns {void}
* @private
*/
function startFunction() {
fns.push(1);
}
/**
* Evaluate the node at the end of function
* @param {ASTNode} node node to evaluate. If it is a `PropertyDefinition` node, its initializer is being evaluated.
* @returns {void}
* @private
*/
function endFunction(node) {
const complexity = fns.pop();
if (complexity > THRESHOLD) {
let evaluatedNode, name;
if (node.type === "PropertyDefinition") {
evaluatedNode = node.value;
name = "class field initializer";
} else {
evaluatedNode = node;
name = astUtils.getFunctionNameWithKind(node);
}
context.report({
node: evaluatedNode,
messageId: "complex",
data: {
name: upperCaseFirst(name),
complexity,
max: THRESHOLD
}
});
}
}
/**
* Increase the complexity of the function in context
* @returns {void}
* @private
*/
function increaseComplexity() {
if (fns.length) {
fns[fns.length - 1]++;
}
}
/**
* Increase the switch complexity in context
* @param {ASTNode} node node to evaluate
* @returns {void}
* @private
*/
function increaseSwitchComplexity(node) {
// Avoiding `default`
if (node.test) {
increaseComplexity();
}
}
//--------------------------------------------------------------------------
// Public API
//--------------------------------------------------------------------------
return {
FunctionDeclaration: startFunction,
FunctionExpression: startFunction,
ArrowFunctionExpression: startFunction,
"FunctionDeclaration:exit": endFunction,
"FunctionExpression:exit": endFunction,
"ArrowFunctionExpression:exit": endFunction,
/*
* Class field initializers are implicit functions. Therefore, they shouldn't contribute
* to the enclosing function's complexity, but their own complexity should be evaluated.
* We're using `*.key:exit` here in order to make sure that `startFunction()` is called
* before entering the `.value` node, and thus certainly before other listeners
* (e.g., if the initializer is `a || b`, due to a higher selector specificity
* `PropertyDefinition > *.value` would be called after `LogicalExpression`).
* We're passing the `PropertyDefinition` node instead of `PropertyDefinition.value` node
* to `endFunction(node)` in order to disambiguate between evaluating implicit initializer
* functions and "regular" functions, which may be the `.value` itself, e.g., `x = () => {};`.
*/
"PropertyDefinition[value] > *.key:exit": startFunction,
"PropertyDefinition[value]:exit": endFunction,
CatchClause: increaseComplexity,
ConditionalExpression: increaseComplexity,
LogicalExpression: increaseComplexity,
ForStatement: increaseComplexity,
ForInStatement: increaseComplexity,
ForOfStatement: increaseComplexity,
IfStatement: increaseComplexity,
SwitchCase: increaseSwitchComplexity,
WhileStatement: increaseComplexity,
DoWhileStatement: increaseComplexity,
AssignmentExpression(node) {
if (astUtils.isLogicalAssignmentOperator(node.operator)) {
increaseComplexity();
}
}
};
}
};