1 | /**
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2 | * @fileoverview Rule to enforce grouped require statements for Node.JS
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3 | * @author Raphael Pigulla
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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 | docs: {
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15 | description: "disallow `require` calls to be mixed with regular variable declarations",
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16 | category: "Node.js and CommonJS",
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17 | recommended: false
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18 | },
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19 |
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20 | schema: [
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21 | {
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22 | oneOf: [
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23 | {
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24 | type: "boolean"
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25 | },
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26 | {
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27 | type: "object",
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28 | properties: {
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29 | grouping: {
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30 | type: "boolean"
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31 | },
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32 | allowCall: {
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33 | type: "boolean"
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34 | }
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35 | },
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36 | additionalProperties: false
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37 | }
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38 | ]
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39 | }
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40 | ]
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41 | },
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42 |
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43 | create(context) {
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44 |
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45 | const options = context.options[0];
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46 | let grouping = false,
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47 | allowCall = false;
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48 |
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49 | if (typeof options === "object") {
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50 | grouping = options.grouping;
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51 | allowCall = options.allowCall;
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52 | } else {
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53 | grouping = !!options;
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54 | }
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55 |
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56 | /**
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57 | * Returns the list of built-in modules.
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58 | *
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59 | * @returns {string[]} An array of built-in Node.js modules.
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60 | */
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61 | function getBuiltinModules() {
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62 |
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63 | /*
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64 | * This list is generated using:
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65 | * `require("repl")._builtinLibs.concat('repl').sort()`
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66 | * This particular list is as per nodejs v0.12.2 and iojs v0.7.1
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67 | */
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68 | return [
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69 | "assert", "buffer", "child_process", "cluster", "crypto",
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70 | "dgram", "dns", "domain", "events", "fs", "http", "https",
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71 | "net", "os", "path", "punycode", "querystring", "readline",
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72 | "repl", "smalloc", "stream", "string_decoder", "tls", "tty",
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73 | "url", "util", "v8", "vm", "zlib"
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74 | ];
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75 | }
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76 |
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77 | const BUILTIN_MODULES = getBuiltinModules();
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78 |
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79 | const DECL_REQUIRE = "require",
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80 | DECL_UNINITIALIZED = "uninitialized",
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81 | DECL_OTHER = "other";
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82 |
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83 | const REQ_CORE = "core",
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84 | REQ_FILE = "file",
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85 | REQ_MODULE = "module",
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86 | REQ_COMPUTED = "computed";
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87 |
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88 | /**
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89 | * Determines the type of a declaration statement.
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90 | * @param {ASTNode} initExpression The init node of the VariableDeclarator.
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91 | * @returns {string} The type of declaration represented by the expression.
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92 | */
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93 | function getDeclarationType(initExpression) {
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94 | if (!initExpression) {
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95 |
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96 | // "var x;"
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97 | return DECL_UNINITIALIZED;
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98 | }
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99 |
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100 | if (initExpression.type === "CallExpression" &&
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101 | initExpression.callee.type === "Identifier" &&
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102 | initExpression.callee.name === "require"
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103 | ) {
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104 |
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105 | // "var x = require('util');"
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106 | return DECL_REQUIRE;
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107 | } else if (allowCall &&
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108 | initExpression.type === "CallExpression" &&
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109 | initExpression.callee.type === "CallExpression"
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110 | ) {
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111 |
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112 | // "var x = require('diagnose')('sub-module');"
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113 | return getDeclarationType(initExpression.callee);
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114 | } else if (initExpression.type === "MemberExpression") {
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115 |
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116 | // "var x = require('glob').Glob;"
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117 | return getDeclarationType(initExpression.object);
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118 | }
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119 |
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120 | // "var x = 42;"
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121 | return DECL_OTHER;
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122 | }
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123 |
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124 | /**
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125 | * Determines the type of module that is loaded via require.
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126 | * @param {ASTNode} initExpression The init node of the VariableDeclarator.
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127 | * @returns {string} The module type.
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128 | */
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129 | function inferModuleType(initExpression) {
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130 | if (initExpression.type === "MemberExpression") {
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131 |
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132 | // "var x = require('glob').Glob;"
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133 | return inferModuleType(initExpression.object);
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134 | } else if (initExpression.arguments.length === 0) {
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135 |
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136 | // "var x = require();"
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137 | return REQ_COMPUTED;
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138 | }
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139 |
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140 | const arg = initExpression.arguments[0];
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141 |
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142 | if (arg.type !== "Literal" || typeof arg.value !== "string") {
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143 |
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144 | // "var x = require(42);"
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145 | return REQ_COMPUTED;
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146 | }
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147 |
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148 | if (BUILTIN_MODULES.indexOf(arg.value) !== -1) {
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149 |
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150 | // "var fs = require('fs');"
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151 | return REQ_CORE;
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152 | } else if (/^\.{0,2}\//.test(arg.value)) {
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153 |
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154 | // "var utils = require('./utils');"
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155 | return REQ_FILE;
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156 | } else {
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157 |
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158 | // "var async = require('async');"
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159 | return REQ_MODULE;
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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 if the list of variable declarations is mixed, i.e. whether it
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165 | * contains both require and other declarations.
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166 | * @param {ASTNode} declarations The list of VariableDeclarators.
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167 | * @returns {boolean} True if the declarations are mixed, false if not.
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168 | */
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169 | function isMixed(declarations) {
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170 | const contains = {};
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171 |
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172 | declarations.forEach(function(declaration) {
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173 | const type = getDeclarationType(declaration.init);
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174 |
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175 | contains[type] = true;
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176 | });
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177 |
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178 | return !!(
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179 | contains[DECL_REQUIRE] &&
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180 | (contains[DECL_UNINITIALIZED] || contains[DECL_OTHER])
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181 | );
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182 | }
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183 |
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184 | /**
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185 | * Check if all require declarations in the given list are of the same
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186 | * type.
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187 | * @param {ASTNode} declarations The list of VariableDeclarators.
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188 | * @returns {boolean} True if the declarations are grouped, false if not.
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189 | */
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190 | function isGrouped(declarations) {
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191 | const found = {};
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192 |
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193 | declarations.forEach(function(declaration) {
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194 | if (getDeclarationType(declaration.init) === DECL_REQUIRE) {
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195 | found[inferModuleType(declaration.init)] = true;
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196 | }
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197 | });
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198 |
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199 | return Object.keys(found).length <= 1;
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200 | }
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201 |
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202 |
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203 | return {
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204 |
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205 | VariableDeclaration(node) {
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206 |
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207 | if (isMixed(node.declarations)) {
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208 | context.report(
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209 | node,
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210 | "Do not mix 'require' and other declarations."
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211 | );
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212 | } else if (grouping && !isGrouped(node.declarations)) {
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213 | context.report(
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214 | node,
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215 | "Do not mix core, module, file and computed requires."
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216 | );
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217 | }
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218 | }
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219 | };
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220 |
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221 | }
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222 | };
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