1 | /**
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2 | * @fileoverview Disallow renaming import, export, and destructured assignments to the same name.
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3 | * @author Kai Cataldo
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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 | // Rule Definition
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10 | //------------------------------------------------------------------------------
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11 |
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12 | module.exports = {
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13 | meta: {
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14 | type: "suggestion",
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15 |
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16 | docs: {
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17 | description: "disallow renaming import, export, and destructured assignments to the same name",
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18 | category: "ECMAScript 6",
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19 | recommended: false,
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20 | url: "https://eslint.org/docs/rules/no-useless-rename"
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21 | },
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22 |
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23 | fixable: "code",
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24 |
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25 | schema: [
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26 | {
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27 | type: "object",
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28 | properties: {
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29 | ignoreDestructuring: { type: "boolean", default: false },
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30 | ignoreImport: { type: "boolean", default: false },
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31 | ignoreExport: { type: "boolean", default: false }
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32 | },
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33 | additionalProperties: false
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34 | }
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35 | ]
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36 | },
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37 |
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38 | create(context) {
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39 | const options = context.options[0] || {},
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40 | ignoreDestructuring = options.ignoreDestructuring === true,
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41 | ignoreImport = options.ignoreImport === true,
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42 | ignoreExport = options.ignoreExport === true;
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43 |
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44 | //--------------------------------------------------------------------------
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45 | // Helpers
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46 | //--------------------------------------------------------------------------
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47 |
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48 | /**
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49 | * Reports error for unnecessarily renamed assignments
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50 | * @param {ASTNode} node - node to report
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51 | * @param {ASTNode} initial - node with initial name value
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52 | * @param {ASTNode} result - node with new name value
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53 | * @param {string} type - the type of the offending node
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54 | * @returns {void}
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55 | */
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56 | function reportError(node, initial, result, type) {
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57 | const name = initial.type === "Identifier" ? initial.name : initial.value;
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58 |
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59 | return context.report({
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60 | node,
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61 | message: "{{type}} {{name}} unnecessarily renamed.",
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62 | data: {
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63 | name,
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64 | type
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65 | },
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66 | fix(fixer) {
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67 | return fixer.replaceTextRange([
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68 | initial.range[0],
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69 | result.range[1]
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70 | ], name);
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71 | }
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72 | });
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73 | }
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74 |
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75 | /**
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76 | * Checks whether a destructured assignment is unnecessarily renamed
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77 | * @param {ASTNode} node - node to check
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78 | * @returns {void}
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79 | */
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80 | function checkDestructured(node) {
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81 | if (ignoreDestructuring) {
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82 | return;
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83 | }
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84 |
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85 | const properties = node.properties;
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86 |
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87 | for (let i = 0; i < properties.length; i++) {
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88 | if (properties[i].shorthand) {
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89 | continue;
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90 | }
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91 |
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92 | /**
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93 | * If an ObjectPattern property is computed, we have no idea
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94 | * if a rename is useless or not. If an ObjectPattern property
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95 | * lacks a key, it is likely an ExperimentalRestProperty and
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96 | * so there is no "renaming" occurring here.
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97 | */
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98 | if (properties[i].computed || !properties[i].key) {
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99 | continue;
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100 | }
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101 |
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102 | if (properties[i].key.type === "Identifier" && properties[i].key.name === properties[i].value.name ||
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103 | properties[i].key.type === "Literal" && properties[i].key.value === properties[i].value.name) {
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104 | reportError(properties[i], properties[i].key, properties[i].value, "Destructuring assignment");
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105 | }
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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 | * Checks whether an import is unnecessarily renamed
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111 | * @param {ASTNode} node - node to check
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112 | * @returns {void}
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113 | */
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114 | function checkImport(node) {
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115 | if (ignoreImport) {
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116 | return;
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117 | }
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118 |
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119 | if (node.imported.name === node.local.name &&
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120 | node.imported.range[0] !== node.local.range[0]) {
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121 | reportError(node, node.imported, node.local, "Import");
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122 | }
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123 | }
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124 |
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125 | /**
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126 | * Checks whether an export is unnecessarily renamed
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127 | * @param {ASTNode} node - node to check
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128 | * @returns {void}
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129 | */
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130 | function checkExport(node) {
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131 | if (ignoreExport) {
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132 | return;
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133 | }
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134 |
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135 | if (node.local.name === node.exported.name &&
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136 | node.local.range[0] !== node.exported.range[0]) {
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137 | reportError(node, node.local, node.exported, "Export");
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138 | }
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139 |
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140 | }
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141 |
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142 | //--------------------------------------------------------------------------
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143 | // Public
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144 | //--------------------------------------------------------------------------
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145 |
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146 | return {
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147 | ObjectPattern: checkDestructured,
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148 | ImportSpecifier: checkImport,
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149 | ExportSpecifier: checkExport
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150 | };
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151 | }
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152 | };
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