1 | /**
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2 | * @fileoverview Rule to check empty newline after "var" statement
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3 | * @author Gopal Venkatesan
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4 | * @deprecated
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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 | //------------------------------------------------------------------------------
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10 | // Requirements
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11 | //------------------------------------------------------------------------------
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12 |
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13 | const astUtils = require("../ast-utils");
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14 |
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15 | //------------------------------------------------------------------------------
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16 | // Rule Definition
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17 | //------------------------------------------------------------------------------
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18 |
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19 | module.exports = {
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20 | meta: {
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21 | docs: {
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22 | description: "require or disallow an empty line after variable declarations",
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23 | category: "Stylistic Issues",
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24 | recommended: false,
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25 | replacedBy: ["padding-line-between-statements"],
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26 | url: "https://eslint.org/docs/rules/newline-after-var"
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27 | },
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28 |
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29 | schema: [
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30 | {
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31 | enum: ["never", "always"]
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32 | }
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33 | ],
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34 |
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35 | fixable: "whitespace",
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36 |
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37 | deprecated: true
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38 | },
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39 |
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40 | create(context) {
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41 |
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42 | const ALWAYS_MESSAGE = "Expected blank line after variable declarations.",
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43 | NEVER_MESSAGE = "Unexpected blank line after variable declarations.";
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44 |
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45 | const sourceCode = context.getSourceCode();
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46 |
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47 | // Default `mode` to "always".
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48 | const mode = context.options[0] === "never" ? "never" : "always";
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49 |
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50 | // Cache starting and ending line numbers of comments for faster lookup
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51 | const commentEndLine = sourceCode.getAllComments().reduce((result, token) => {
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52 | result[token.loc.start.line] = token.loc.end.line;
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53 | return result;
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54 | }, {});
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55 |
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56 |
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57 | //--------------------------------------------------------------------------
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58 | // Helpers
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59 | //--------------------------------------------------------------------------
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60 |
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61 | /**
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62 | * Gets a token from the given node to compare line to the next statement.
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63 | *
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64 | * In general, the token is the last token of the node. However, the token is the second last token if the following conditions satisfy.
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65 | *
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66 | * - The last token is semicolon.
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67 | * - The semicolon is on a different line from the previous token of the semicolon.
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68 | *
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69 | * This behavior would address semicolon-less style code. e.g.:
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70 | *
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71 | * var foo = 1
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72 | *
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73 | * ;(a || b).doSomething()
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74 | *
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75 | * @param {ASTNode} node - The node to get.
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76 | * @returns {Token} The token to compare line to the next statement.
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77 | */
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78 | function getLastToken(node) {
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79 | const lastToken = sourceCode.getLastToken(node);
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80 |
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81 | if (lastToken.type === "Punctuator" && lastToken.value === ";") {
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82 | const prevToken = sourceCode.getTokenBefore(lastToken);
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83 |
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84 | if (prevToken.loc.end.line !== lastToken.loc.start.line) {
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85 | return prevToken;
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86 | }
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87 | }
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88 |
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89 | return lastToken;
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90 | }
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91 |
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92 | /**
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93 | * Determine if provided keyword is a variable declaration
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94 | * @private
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95 | * @param {string} keyword - keyword to test
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96 | * @returns {boolean} True if `keyword` is a type of var
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97 | */
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98 | function isVar(keyword) {
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99 | return keyword === "var" || keyword === "let" || keyword === "const";
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100 | }
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101 |
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102 | /**
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103 | * Determine if provided keyword is a variant of for specifiers
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104 | * @private
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105 | * @param {string} keyword - keyword to test
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106 | * @returns {boolean} True if `keyword` is a variant of for specifier
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107 | */
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108 | function isForTypeSpecifier(keyword) {
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109 | return keyword === "ForStatement" || keyword === "ForInStatement" || keyword === "ForOfStatement";
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110 | }
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111 |
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112 | /**
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113 | * Determine if provided keyword is an export specifiers
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114 | * @private
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115 | * @param {string} nodeType - nodeType to test
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116 | * @returns {boolean} True if `nodeType` is an export specifier
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117 | */
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118 | function isExportSpecifier(nodeType) {
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119 | return nodeType === "ExportNamedDeclaration" || nodeType === "ExportSpecifier" ||
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120 | nodeType === "ExportDefaultDeclaration" || nodeType === "ExportAllDeclaration";
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121 | }
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122 |
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123 | /**
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124 | * Determine if provided node is the last of their parent block.
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125 | * @private
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126 | * @param {ASTNode} node - node to test
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127 | * @returns {boolean} True if `node` is last of their parent block.
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128 | */
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129 | function isLastNode(node) {
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130 | const token = sourceCode.getTokenAfter(node);
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131 |
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132 | return !token || (token.type === "Punctuator" && token.value === "}");
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133 | }
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134 |
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135 | /**
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136 | * Gets the last line of a group of consecutive comments
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137 | * @param {number} commentStartLine The starting line of the group
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138 | * @returns {number} The number of the last comment line of the group
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139 | */
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140 | function getLastCommentLineOfBlock(commentStartLine) {
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141 | const currentCommentEnd = commentEndLine[commentStartLine];
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142 |
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143 | return commentEndLine[currentCommentEnd + 1] ? getLastCommentLineOfBlock(currentCommentEnd + 1) : currentCommentEnd;
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144 | }
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145 |
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146 | /**
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147 | * Determine if a token starts more than one line after a comment ends
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148 | * @param {token} token The token being checked
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149 | * @param {integer} commentStartLine The line number on which the comment starts
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150 | * @returns {boolean} True if `token` does not start immediately after a comment
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151 | */
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152 | function hasBlankLineAfterComment(token, commentStartLine) {
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153 | return token.loc.start.line > getLastCommentLineOfBlock(commentStartLine) + 1;
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154 | }
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155 |
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156 | /**
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157 | * Checks that a blank line exists after a variable declaration when mode is
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158 | * set to "always", or checks that there is no blank line when mode is set
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159 | * to "never"
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160 | * @private
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161 | * @param {ASTNode} node - `VariableDeclaration` node to test
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162 | * @returns {void}
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163 | */
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164 | function checkForBlankLine(node) {
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165 |
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166 | /*
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167 | * lastToken is the last token on the node's line. It will usually also be the last token of the node, but it will
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168 | * sometimes be second-last if there is a semicolon on a different line.
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169 | */
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170 | const lastToken = getLastToken(node),
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171 |
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172 | /*
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173 | * If lastToken is the last token of the node, nextToken should be the token after the node. Otherwise, nextToken
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174 | * is the last token of the node.
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175 | */
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176 | nextToken = lastToken === sourceCode.getLastToken(node) ? sourceCode.getTokenAfter(node) : sourceCode.getLastToken(node),
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177 | nextLineNum = lastToken.loc.end.line + 1;
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178 |
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179 | // Ignore if there is no following statement
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180 | if (!nextToken) {
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181 | return;
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182 | }
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183 |
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184 | // Ignore if parent of node is a for variant
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185 | if (isForTypeSpecifier(node.parent.type)) {
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186 | return;
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187 | }
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188 |
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189 | // Ignore if parent of node is an export specifier
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190 | if (isExportSpecifier(node.parent.type)) {
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191 | return;
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192 | }
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193 |
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194 | /*
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195 | * Some coding styles use multiple `var` statements, so do nothing if
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196 | * the next token is a `var` statement.
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197 | */
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198 | if (nextToken.type === "Keyword" && isVar(nextToken.value)) {
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199 | return;
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200 | }
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201 |
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202 | // Ignore if it is last statement in a block
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203 | if (isLastNode(node)) {
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204 | return;
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205 | }
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206 |
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207 | // Next statement is not a `var`...
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208 | const noNextLineToken = nextToken.loc.start.line > nextLineNum;
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209 | const hasNextLineComment = (typeof commentEndLine[nextLineNum] !== "undefined");
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210 |
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211 | if (mode === "never" && noNextLineToken && !hasNextLineComment) {
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212 | context.report({
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213 | node,
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214 | message: NEVER_MESSAGE,
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215 | data: { identifier: node.name },
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216 | fix(fixer) {
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217 | const linesBetween = sourceCode.getText().slice(lastToken.range[1], nextToken.range[0]).split(astUtils.LINEBREAK_MATCHER);
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218 |
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219 | return fixer.replaceTextRange([lastToken.range[1], nextToken.range[0]], `${linesBetween.slice(0, -1).join("")}\n${linesBetween[linesBetween.length - 1]}`);
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220 | }
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221 | });
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222 | }
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223 |
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224 | // Token on the next line, or comment without blank line
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225 | if (
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226 | mode === "always" && (
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227 | !noNextLineToken ||
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228 | hasNextLineComment && !hasBlankLineAfterComment(nextToken, nextLineNum)
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229 | )
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230 | ) {
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231 | context.report({
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232 | node,
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233 | message: ALWAYS_MESSAGE,
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234 | data: { identifier: node.name },
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235 | fix(fixer) {
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236 | if ((noNextLineToken ? getLastCommentLineOfBlock(nextLineNum) : lastToken.loc.end.line) === nextToken.loc.start.line) {
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237 | return fixer.insertTextBefore(nextToken, "\n\n");
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238 | }
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239 |
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240 | return fixer.insertTextBeforeRange([nextToken.range[0] - nextToken.loc.start.column, nextToken.range[1]], "\n");
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241 | }
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242 | });
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243 | }
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244 | }
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245 |
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246 | //--------------------------------------------------------------------------
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247 | // Public
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248 | //--------------------------------------------------------------------------
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249 |
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250 | return {
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251 | VariableDeclaration: checkForBlankLine
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252 | };
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253 |
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254 | }
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255 | };
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