166 lines
		
	
	
		
			5.6 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			166 lines
		
	
	
		
			5.6 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
/**
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 * @fileoverview Counts the cyclomatic complexity of each function of the script. See http://en.wikipedia.org/wiki/Cyclomatic_complexity.
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 * Counts the number of if, conditional, for, while, try, switch/case,
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 * @author Patrick Brosset
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 */
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"use strict";
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//------------------------------------------------------------------------------
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// Requirements
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//------------------------------------------------------------------------------
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const astUtils = require("./utils/ast-utils");
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const { upperCaseFirst } = require("../shared/string-utils");
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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/** @type {import('../shared/types').Rule} */
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module.exports = {
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    meta: {
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        type: "suggestion",
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        docs: {
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            description: "Enforce a maximum cyclomatic complexity allowed in a program",
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            recommended: false,
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            url: "https://eslint.org/docs/latest/rules/complexity"
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        },
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        schema: [
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            {
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                oneOf: [
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                    {
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                        type: "integer",
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                        minimum: 0
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                    },
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                    {
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                        type: "object",
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                        properties: {
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                            maximum: {
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                                type: "integer",
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                                minimum: 0
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                            },
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                            max: {
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                                type: "integer",
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                                minimum: 0
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                            }
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                        },
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                        additionalProperties: false
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                    }
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                ]
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            }
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        ],
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        messages: {
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            complex: "{{name}} has a complexity of {{complexity}}. Maximum allowed is {{max}}."
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        }
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    },
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    create(context) {
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        const option = context.options[0];
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        let THRESHOLD = 20;
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        if (
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            typeof option === "object" &&
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            (Object.prototype.hasOwnProperty.call(option, "maximum") || Object.prototype.hasOwnProperty.call(option, "max"))
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        ) {
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            THRESHOLD = option.maximum || option.max;
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        } else if (typeof option === "number") {
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            THRESHOLD = option;
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        }
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        //--------------------------------------------------------------------------
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        // Helpers
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        //--------------------------------------------------------------------------
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        // Using a stack to store complexity per code path
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        const complexities = [];
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        /**
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         * Increase the complexity of the code path in context
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         * @returns {void}
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         * @private
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         */
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        function increaseComplexity() {
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            complexities[complexities.length - 1]++;
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        }
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        //--------------------------------------------------------------------------
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        // Public API
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        //--------------------------------------------------------------------------
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        return {
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            onCodePathStart() {
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                // The initial complexity is 1, representing one execution path in the CodePath
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                complexities.push(1);
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            },
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            // Each branching in the code adds 1 to the complexity
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            CatchClause: increaseComplexity,
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            ConditionalExpression: increaseComplexity,
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            LogicalExpression: increaseComplexity,
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            ForStatement: increaseComplexity,
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            ForInStatement: increaseComplexity,
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            ForOfStatement: increaseComplexity,
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            IfStatement: increaseComplexity,
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            WhileStatement: increaseComplexity,
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            DoWhileStatement: increaseComplexity,
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            // Avoid `default`
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            "SwitchCase[test]": increaseComplexity,
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            // Logical assignment operators have short-circuiting behavior
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            AssignmentExpression(node) {
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                if (astUtils.isLogicalAssignmentOperator(node.operator)) {
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                    increaseComplexity();
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                }
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            },
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            onCodePathEnd(codePath, node) {
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                const complexity = complexities.pop();
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                /*
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                 * This rule only evaluates complexity of functions, so "program" is excluded.
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                 * Class field initializers and class static blocks are implicit functions. Therefore,
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                 * they shouldn't contribute to the enclosing function's complexity, but their
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                 * own complexity should be evaluated.
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                 */
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                if (
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                    codePath.origin !== "function" &&
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                    codePath.origin !== "class-field-initializer" &&
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                    codePath.origin !== "class-static-block"
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                ) {
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                    return;
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                }
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                if (complexity > THRESHOLD) {
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                    let name;
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                    if (codePath.origin === "class-field-initializer") {
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                        name = "class field initializer";
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                    } else if (codePath.origin === "class-static-block") {
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                        name = "class static block";
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                    } else {
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                        name = astUtils.getFunctionNameWithKind(node);
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                    }
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                    context.report({
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                        node,
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                        messageId: "complex",
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                        data: {
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                            name: upperCaseFirst(name),
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                            complexity,
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                            max: THRESHOLD
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                        }
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                    });
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                }
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            }
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        };
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    }
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};
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