1 | /**
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2 | * @fileoverview Rule to flag use of parseInt without a radix argument
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3 | * @author James Allardice
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4 | */
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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 | // Requirements
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10 | //------------------------------------------------------------------------------
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11 |
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12 | const astUtils = require("./utils/ast-utils");
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13 |
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14 | //------------------------------------------------------------------------------
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15 | // Helpers
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16 | //------------------------------------------------------------------------------
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17 |
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18 | const MODE_ALWAYS = "always",
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19 | MODE_AS_NEEDED = "as-needed";
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20 |
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21 | const validRadixValues = new Set(Array.from({ length: 37 - 2 }, (_, index) => index + 2));
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22 |
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23 | /**
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24 | * Checks whether a given variable is shadowed or not.
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25 | * @param {eslint-scope.Variable} variable A variable to check.
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26 | * @returns {boolean} `true` if the variable is shadowed.
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27 | */
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28 | function isShadowed(variable) {
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29 | return variable.defs.length >= 1;
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30 | }
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31 |
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32 | /**
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33 | * Checks whether a given node is a MemberExpression of `parseInt` method or not.
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34 | * @param {ASTNode} node A node to check.
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35 | * @returns {boolean} `true` if the node is a MemberExpression of `parseInt`
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36 | * method.
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37 | */
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38 | function isParseIntMethod(node) {
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39 | return (
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40 | node.type === "MemberExpression" &&
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41 | !node.computed &&
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42 | node.property.type === "Identifier" &&
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43 | node.property.name === "parseInt"
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44 | );
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45 | }
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46 |
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47 | /**
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48 | * Checks whether a given node is a valid value of radix or not.
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49 | *
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50 | * The following values are invalid.
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51 | *
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52 | * - A literal except integers between 2 and 36.
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53 | * - undefined.
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54 | * @param {ASTNode} radix A node of radix to check.
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55 | * @returns {boolean} `true` if the node is valid.
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56 | */
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57 | function isValidRadix(radix) {
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58 | return !(
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59 | (radix.type === "Literal" && !validRadixValues.has(radix.value)) ||
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60 | (radix.type === "Identifier" && radix.name === "undefined")
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61 | );
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62 | }
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63 |
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64 | /**
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65 | * Checks whether a given node is a default value of radix or not.
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66 | * @param {ASTNode} radix A node of radix to check.
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67 | * @returns {boolean} `true` if the node is the literal node of `10`.
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68 | */
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69 | function isDefaultRadix(radix) {
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70 | return radix.type === "Literal" && radix.value === 10;
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71 | }
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72 |
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73 | //------------------------------------------------------------------------------
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74 | // Rule Definition
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75 | //------------------------------------------------------------------------------
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76 |
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77 | module.exports = {
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78 | meta: {
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79 | type: "suggestion",
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80 |
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81 | docs: {
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82 | description: "enforce the consistent use of the radix argument when using `parseInt()`",
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83 | category: "Best Practices",
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84 | recommended: false,
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85 | url: "https://eslint.org/docs/rules/radix"
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86 | },
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87 |
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88 | schema: [
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89 | {
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90 | enum: ["always", "as-needed"]
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91 | }
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92 | ],
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93 |
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94 | messages: {
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95 | missingParameters: "Missing parameters.",
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96 | redundantRadix: "Redundant radix parameter.",
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97 | missingRadix: "Missing radix parameter.",
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98 | invalidRadix: "Invalid radix parameter, must be an integer between 2 and 36."
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99 | }
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100 | },
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101 |
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102 | create(context) {
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103 | const mode = context.options[0] || MODE_ALWAYS;
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104 |
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105 | /**
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106 | * Checks the arguments of a given CallExpression node and reports it if it
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107 | * offends this rule.
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108 | * @param {ASTNode} node A CallExpression node to check.
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109 | * @returns {void}
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110 | */
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111 | function checkArguments(node) {
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112 | const args = node.arguments;
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113 |
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114 | switch (args.length) {
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115 | case 0:
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116 | context.report({
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117 | node,
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118 | messageId: "missingParameters"
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119 | });
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120 | break;
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121 |
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122 | case 1:
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123 | if (mode === MODE_ALWAYS) {
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124 | context.report({
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125 | node,
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126 | messageId: "missingRadix"
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127 | });
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128 | }
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129 | break;
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130 |
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131 | default:
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132 | if (mode === MODE_AS_NEEDED && isDefaultRadix(args[1])) {
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133 | context.report({
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134 | node,
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135 | messageId: "redundantRadix"
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136 | });
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137 | } else if (!isValidRadix(args[1])) {
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138 | context.report({
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139 | node,
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140 | messageId: "invalidRadix"
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141 | });
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142 | }
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143 | break;
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144 | }
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145 | }
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146 |
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147 | return {
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148 | "Program:exit"() {
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149 | const scope = context.getScope();
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150 | let variable;
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151 |
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152 | // Check `parseInt()`
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153 | variable = astUtils.getVariableByName(scope, "parseInt");
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154 | if (variable && !isShadowed(variable)) {
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155 | variable.references.forEach(reference => {
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156 | const node = reference.identifier;
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157 |
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158 | if (astUtils.isCallee(node)) {
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159 | checkArguments(node.parent);
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160 | }
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161 | });
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162 | }
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163 |
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164 | // Check `Number.parseInt()`
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165 | variable = astUtils.getVariableByName(scope, "Number");
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166 | if (variable && !isShadowed(variable)) {
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167 | variable.references.forEach(reference => {
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168 | const node = reference.identifier.parent;
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169 | const maybeCallee = node.parent.type === "ChainExpression"
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170 | ? node.parent
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171 | : node;
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172 |
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173 | if (isParseIntMethod(node) && astUtils.isCallee(maybeCallee)) {
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174 | checkArguments(maybeCallee.parent);
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175 | }
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176 | });
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177 | }
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178 | }
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179 | };
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180 | }
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181 | };
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