1 | /**
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2 | * @fileoverview Rule to flag use of alert, confirm, prompt
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3 | * @author Nicholas C. Zakas
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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 | // Requirements
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9 | //------------------------------------------------------------------------------
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10 |
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11 | const {
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12 | getStaticPropertyName: getPropertyName,
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13 | getVariableByName,
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14 | skipChainExpression
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15 | } = require("./utils/ast-utils");
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16 |
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17 | //------------------------------------------------------------------------------
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18 | // Helpers
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19 | //------------------------------------------------------------------------------
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20 |
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21 | /**
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22 | * Checks if the given name is a prohibited identifier.
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23 | * @param {string} name The name to check
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24 | * @returns {boolean} Whether or not the name is prohibited.
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25 | */
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26 | function isProhibitedIdentifier(name) {
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27 | return /^(alert|confirm|prompt)$/u.test(name);
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28 | }
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29 |
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30 | /**
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31 | * Finds the eslint-scope reference in the given scope.
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32 | * @param {Object} scope The scope to search.
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33 | * @param {ASTNode} node The identifier node.
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34 | * @returns {Reference|null} Returns the found reference or null if none were found.
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35 | */
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36 | function findReference(scope, node) {
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37 | const references = scope.references.filter(reference => reference.identifier.range[0] === node.range[0] &&
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38 | reference.identifier.range[1] === node.range[1]);
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39 |
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40 | if (references.length === 1) {
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41 | return references[0];
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42 | }
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43 | return null;
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44 | }
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45 |
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46 | /**
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47 | * Checks if the given identifier node is shadowed in the given scope.
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48 | * @param {Object} scope The current scope.
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49 | * @param {string} node The identifier node to check
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50 | * @returns {boolean} Whether or not the name is shadowed.
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51 | */
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52 | function isShadowed(scope, node) {
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53 | const reference = findReference(scope, node);
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54 |
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55 | return reference && reference.resolved && reference.resolved.defs.length > 0;
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56 | }
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57 |
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58 | /**
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59 | * Checks if the given identifier node is a ThisExpression in the global scope or the global window property.
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60 | * @param {Object} scope The current scope.
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61 | * @param {string} node The identifier node to check
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62 | * @returns {boolean} Whether or not the node is a reference to the global object.
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63 | */
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64 | function isGlobalThisReferenceOrGlobalWindow(scope, node) {
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65 | if (scope.type === "global" && node.type === "ThisExpression") {
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66 | return true;
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67 | }
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68 | if (
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69 | node.type === "Identifier" &&
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70 | (
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71 | node.name === "window" ||
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72 | (node.name === "globalThis" && getVariableByName(scope, "globalThis"))
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73 | )
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74 | ) {
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75 | return !isShadowed(scope, node);
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76 | }
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77 |
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78 | return false;
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79 | }
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80 |
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81 | //------------------------------------------------------------------------------
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82 | // Rule Definition
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83 | //------------------------------------------------------------------------------
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84 |
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85 | module.exports = {
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86 | meta: {
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87 | type: "suggestion",
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88 |
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89 | docs: {
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90 | description: "disallow the use of `alert`, `confirm`, and `prompt`",
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91 | category: "Best Practices",
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92 | recommended: false,
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93 | url: "https://eslint.org/docs/rules/no-alert"
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94 | },
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95 |
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96 | schema: [],
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97 |
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98 | messages: {
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99 | unexpected: "Unexpected {{name}}."
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100 | }
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101 | },
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102 |
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103 | create(context) {
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104 | return {
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105 | CallExpression(node) {
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106 | const callee = skipChainExpression(node.callee),
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107 | currentScope = context.getScope();
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108 |
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109 | // without window.
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110 | if (callee.type === "Identifier") {
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111 | const name = callee.name;
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112 |
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113 | if (!isShadowed(currentScope, callee) && isProhibitedIdentifier(callee.name)) {
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114 | context.report({
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115 | node,
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116 | messageId: "unexpected",
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117 | data: { name }
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118 | });
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119 | }
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120 |
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121 | } else if (callee.type === "MemberExpression" && isGlobalThisReferenceOrGlobalWindow(currentScope, callee.object)) {
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122 | const name = getPropertyName(callee);
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123 |
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124 | if (isProhibitedIdentifier(name)) {
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125 | context.report({
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126 | node,
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127 | messageId: "unexpected",
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128 | data: { name }
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129 | });
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130 | }
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131 | }
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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 | };
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