1 | /**
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2 | * @fileoverview Counts the cyclomatic complexity of each function of the script. See http://en.wikipedia.org/wiki/Cyclomatic_complexity.
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3 | * Counts the number of if, conditional, for, while, try, switch/case,
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4 | * @author Patrick Brosset
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5 | */
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6 |
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7 | ;
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8 |
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9 | //------------------------------------------------------------------------------
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10 | // Requirements
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11 | //------------------------------------------------------------------------------
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12 |
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13 | const lodash = require("lodash");
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14 |
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15 | const astUtils = require("./utils/ast-utils");
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16 |
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17 | //------------------------------------------------------------------------------
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18 | // Rule Definition
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19 | //------------------------------------------------------------------------------
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20 |
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21 | module.exports = {
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22 | meta: {
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23 | type: "suggestion",
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24 |
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25 | docs: {
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26 | description: "enforce a maximum cyclomatic complexity allowed in a program",
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27 | category: "Best Practices",
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28 | recommended: false,
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29 | url: "https://eslint.org/docs/rules/complexity"
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30 | },
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31 |
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32 | schema: [
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33 | {
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34 | oneOf: [
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35 | {
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36 | type: "integer",
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37 | minimum: 0
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38 | },
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39 | {
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40 | type: "object",
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41 | properties: {
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42 | maximum: {
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43 | type: "integer",
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44 | minimum: 0
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45 | },
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46 | max: {
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47 | type: "integer",
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48 | minimum: 0
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49 | }
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50 | },
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51 | additionalProperties: false
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52 | }
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53 | ]
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54 | }
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55 | ],
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56 |
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57 | messages: {
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58 | complex: "{{name}} has a complexity of {{complexity}}. Maximum allowed is {{max}}."
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59 | }
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60 | },
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61 |
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62 | create(context) {
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63 | const option = context.options[0];
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64 | let THRESHOLD = 20;
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65 |
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66 | if (
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67 | typeof option === "object" &&
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68 | (Object.prototype.hasOwnProperty.call(option, "maximum") || Object.prototype.hasOwnProperty.call(option, "max"))
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69 | ) {
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70 | THRESHOLD = option.maximum || option.max;
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71 | } else if (typeof option === "number") {
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72 | THRESHOLD = option;
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73 | }
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74 |
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75 | //--------------------------------------------------------------------------
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76 | // Helpers
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77 | //--------------------------------------------------------------------------
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78 |
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79 | // Using a stack to store complexity (handling nested functions)
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80 | const fns = [];
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81 |
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82 | /**
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83 | * When parsing a new function, store it in our function stack
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84 | * @returns {void}
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85 | * @private
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86 | */
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87 | function startFunction() {
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88 | fns.push(1);
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89 | }
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90 |
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91 | /**
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92 | * Evaluate the node at the end of function
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93 | * @param {ASTNode} node node to evaluate
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94 | * @returns {void}
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95 | * @private
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96 | */
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97 | function endFunction(node) {
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98 | const name = lodash.upperFirst(astUtils.getFunctionNameWithKind(node));
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99 | const complexity = fns.pop();
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100 |
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101 | if (complexity > THRESHOLD) {
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102 | context.report({
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103 | node,
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104 | messageId: "complex",
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105 | data: { name, complexity, max: THRESHOLD }
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106 | });
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107 | }
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108 | }
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109 |
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110 | /**
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111 | * Increase the complexity of the function in context
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112 | * @returns {void}
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113 | * @private
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114 | */
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115 | function increaseComplexity() {
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116 | if (fns.length) {
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117 | fns[fns.length - 1]++;
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118 | }
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119 | }
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120 |
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121 | /**
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122 | * Increase the switch complexity in context
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123 | * @param {ASTNode} node node to evaluate
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124 | * @returns {void}
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125 | * @private
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126 | */
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127 | function increaseSwitchComplexity(node) {
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128 |
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129 | // Avoiding `default`
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130 | if (node.test) {
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131 | increaseComplexity();
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132 | }
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133 | }
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134 |
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135 | //--------------------------------------------------------------------------
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136 | // Public API
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137 | //--------------------------------------------------------------------------
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138 |
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139 | return {
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140 | FunctionDeclaration: startFunction,
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141 | FunctionExpression: startFunction,
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142 | ArrowFunctionExpression: startFunction,
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143 | "FunctionDeclaration:exit": endFunction,
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144 | "FunctionExpression:exit": endFunction,
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145 | "ArrowFunctionExpression:exit": endFunction,
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146 |
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147 | CatchClause: increaseComplexity,
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148 | ConditionalExpression: increaseComplexity,
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149 | LogicalExpression: increaseComplexity,
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150 | ForStatement: increaseComplexity,
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151 | ForInStatement: increaseComplexity,
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152 | ForOfStatement: increaseComplexity,
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153 | IfStatement: increaseComplexity,
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154 | SwitchCase: increaseSwitchComplexity,
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155 | WhileStatement: increaseComplexity,
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156 | DoWhileStatement: increaseComplexity,
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157 |
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158 | AssignmentExpression(node) {
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159 | if (astUtils.isLogicalAssignmentOperator(node.operator)) {
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160 | increaseComplexity();
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161 | }
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162 | }
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163 | };
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164 |
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165 | }
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166 | };
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