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("../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 | /**
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22 | * Checks whether a given variable is shadowed or not.
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23 | *
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24 | * @param {escope.Variable} variable - A variable to check.
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25 | * @returns {boolean} `true` if the variable is shadowed.
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26 | */
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27 | function isShadowed(variable) {
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28 | return variable.defs.length >= 1;
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29 | }
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30 |
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31 | /**
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32 | * Checks whether a given node is a MemberExpression of `parseInt` method or not.
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33 | *
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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 numbers.
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53 | * - undefined.
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54 | *
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55 | * @param {ASTNode} radix - A node of radix to check.
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56 | * @returns {boolean} `true` if the node is valid.
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57 | */
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58 | function isValidRadix(radix) {
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59 | return !(
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60 | (radix.type === "Literal" && typeof radix.value !== "number") ||
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61 | (radix.type === "Identifier" && radix.name === "undefined")
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62 | );
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63 | }
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64 |
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65 | /**
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66 | * Checks whether a given node is a default value of radix or not.
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67 | *
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68 | * @param {ASTNode} radix - A node of radix to check.
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69 | * @returns {boolean} `true` if the node is the literal node of `10`.
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70 | */
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71 | function isDefaultRadix(radix) {
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72 | return radix.type === "Literal" && radix.value === 10;
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73 | }
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74 |
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75 | //------------------------------------------------------------------------------
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76 | // Rule Definition
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77 | //------------------------------------------------------------------------------
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78 |
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79 | module.exports = {
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80 | meta: {
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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 | },
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86 |
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87 | schema: [
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88 | {
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89 | enum: ["always", "as-needed"]
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90 | }
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91 | ]
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92 | },
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93 |
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94 | create(context) {
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95 | const mode = context.options[0] || MODE_ALWAYS;
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96 |
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97 | /**
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98 | * Checks the arguments of a given CallExpression node and reports it if it
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99 | * offends this rule.
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100 | *
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101 | * @param {ASTNode} node - A CallExpression node to check.
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102 | * @returns {void}
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103 | */
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104 | function checkArguments(node) {
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105 | const args = node.arguments;
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106 |
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107 | switch (args.length) {
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108 | case 0:
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109 | context.report({
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110 | node,
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111 | message: "Missing parameters."
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112 | });
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113 | break;
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114 |
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115 | case 1:
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116 | if (mode === MODE_ALWAYS) {
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117 | context.report({
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118 | node,
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119 | message: "Missing radix parameter."
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120 | });
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121 | }
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122 | break;
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123 |
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124 | default:
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125 | if (mode === MODE_AS_NEEDED && isDefaultRadix(args[1])) {
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126 | context.report({
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127 | node,
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128 | message: "Redundant radix parameter."
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129 | });
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130 | } else if (!isValidRadix(args[1])) {
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131 | context.report({
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132 | node,
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133 | message: "Invalid radix parameter."
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134 | });
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135 | }
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136 | break;
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137 | }
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138 | }
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139 |
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140 | return {
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141 | "Program:exit"() {
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142 | const scope = context.getScope();
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143 | let variable;
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144 |
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145 | // Check `parseInt()`
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146 | variable = astUtils.getVariableByName(scope, "parseInt");
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147 | if (!isShadowed(variable)) {
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148 | variable.references.forEach(function(reference) {
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149 | const node = reference.identifier;
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150 |
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151 | if (astUtils.isCallee(node)) {
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152 | checkArguments(node.parent);
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153 | }
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154 | });
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155 | }
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156 |
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157 | // Check `Number.parseInt()`
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158 | variable = astUtils.getVariableByName(scope, "Number");
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159 | if (!isShadowed(variable)) {
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160 | variable.references.forEach(function(reference) {
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161 | const node = reference.identifier.parent;
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162 |
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163 | if (isParseIntMethod(node) && astUtils.isCallee(node)) {
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164 | checkArguments(node.parent);
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165 | }
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166 | });
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167 | }
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168 | }
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169 | };
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170 | }
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171 | };
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