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("./utils/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 | type: "layout",
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22 |
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23 | docs: {
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24 | description: "require or disallow an empty line after variable declarations",
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25 | category: "Stylistic Issues",
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26 | recommended: false,
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27 | url: "https://eslint.org/docs/rules/newline-after-var"
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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 | fixable: "whitespace",
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35 | messages: {
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36 | expected: "Expected blank line after variable declarations.",
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37 | unexpected: "Unexpected blank line after variable declarations."
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38 | },
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39 |
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40 | deprecated: true,
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41 |
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42 | replacedBy: ["padding-line-between-statements"]
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43 | },
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44 |
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45 | create(context) {
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46 | const sourceCode = context.getSourceCode();
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47 |
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48 | // Default `mode` to "always".
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49 | const mode = context.options[0] === "never" ? "never" : "always";
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50 |
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51 | // Cache starting and ending line numbers of comments for faster lookup
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52 | const commentEndLine = sourceCode.getAllComments().reduce((result, token) => {
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53 | result[token.loc.start.line] = token.loc.end.line;
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54 | return result;
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55 | }, {});
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56 |
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57 |
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58 | //--------------------------------------------------------------------------
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59 | // Helpers
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60 | //--------------------------------------------------------------------------
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61 |
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62 | /**
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63 | * Gets a token from the given node to compare line to the next statement.
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64 | *
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65 | * 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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66 | *
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67 | * - The last token is semicolon.
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68 | * - The semicolon is on a different line from the previous token of the semicolon.
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69 | *
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70 | * This behavior would address semicolon-less style code. e.g.:
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71 | *
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72 | * var foo = 1
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73 | *
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74 | * ;(a || b).doSomething()
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75 | *
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76 | * @param {ASTNode} node - The node to get.
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77 | * @returns {Token} The token to compare line to the next statement.
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78 | */
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79 | function getLastToken(node) {
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80 | const lastToken = sourceCode.getLastToken(node);
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81 |
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82 | if (lastToken.type === "Punctuator" && lastToken.value === ";") {
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83 | const prevToken = sourceCode.getTokenBefore(lastToken);
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84 |
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85 | if (prevToken.loc.end.line !== lastToken.loc.start.line) {
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86 | return prevToken;
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87 | }
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88 | }
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89 |
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90 | return lastToken;
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91 | }
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92 |
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93 | /**
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94 | * Determine if provided keyword is a variable declaration
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95 | * @private
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96 | * @param {string} keyword - keyword to test
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97 | * @returns {boolean} True if `keyword` is a type of var
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98 | */
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99 | function isVar(keyword) {
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100 | return keyword === "var" || keyword === "let" || keyword === "const";
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101 | }
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102 |
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103 | /**
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104 | * Determine if provided keyword is a variant of for specifiers
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105 | * @private
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106 | * @param {string} keyword - keyword to test
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107 | * @returns {boolean} True if `keyword` is a variant of for specifier
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108 | */
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109 | function isForTypeSpecifier(keyword) {
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110 | return keyword === "ForStatement" || keyword === "ForInStatement" || keyword === "ForOfStatement";
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111 | }
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112 |
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113 | /**
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114 | * Determine if provided keyword is an export specifiers
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115 | * @private
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116 | * @param {string} nodeType - nodeType to test
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117 | * @returns {boolean} True if `nodeType` is an export specifier
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118 | */
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119 | function isExportSpecifier(nodeType) {
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120 | return nodeType === "ExportNamedDeclaration" || nodeType === "ExportSpecifier" ||
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121 | nodeType === "ExportDefaultDeclaration" || nodeType === "ExportAllDeclaration";
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122 | }
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123 |
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124 | /**
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125 | * Determine if provided node is the last of their parent block.
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126 | * @private
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127 | * @param {ASTNode} node - node to test
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128 | * @returns {boolean} True if `node` is last of their parent block.
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129 | */
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130 | function isLastNode(node) {
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131 | const token = sourceCode.getTokenAfter(node);
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132 |
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133 | return !token || (token.type === "Punctuator" && token.value === "}");
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134 | }
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135 |
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136 | /**
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137 | * Gets the last line of a group of consecutive comments
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138 | * @param {number} commentStartLine The starting line of the group
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139 | * @returns {number} The number of the last comment line of the group
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140 | */
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141 | function getLastCommentLineOfBlock(commentStartLine) {
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142 | const currentCommentEnd = commentEndLine[commentStartLine];
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143 |
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144 | return commentEndLine[currentCommentEnd + 1] ? getLastCommentLineOfBlock(currentCommentEnd + 1) : currentCommentEnd;
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145 | }
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146 |
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147 | /**
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148 | * Determine if a token starts more than one line after a comment ends
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149 | * @param {token} token The token being checked
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150 | * @param {integer} commentStartLine The line number on which the comment starts
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151 | * @returns {boolean} True if `token` does not start immediately after a comment
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152 | */
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153 | function hasBlankLineAfterComment(token, commentStartLine) {
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154 | return token.loc.start.line > getLastCommentLineOfBlock(commentStartLine) + 1;
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155 | }
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156 |
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157 | /**
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158 | * Checks that a blank line exists after a variable declaration when mode is
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159 | * set to "always", or checks that there is no blank line when mode is set
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160 | * to "never"
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161 | * @private
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162 | * @param {ASTNode} node - `VariableDeclaration` node to test
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163 | * @returns {void}
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164 | */
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165 | function checkForBlankLine(node) {
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166 |
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167 | /*
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168 | * 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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169 | * sometimes be second-last if there is a semicolon on a different line.
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170 | */
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171 | const lastToken = getLastToken(node),
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172 |
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173 | /*
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174 | * If lastToken is the last token of the node, nextToken should be the token after the node. Otherwise, nextToken
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175 | * is the last token of the node.
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176 | */
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177 | nextToken = lastToken === sourceCode.getLastToken(node) ? sourceCode.getTokenAfter(node) : sourceCode.getLastToken(node),
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178 | nextLineNum = lastToken.loc.end.line + 1;
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179 |
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180 | // Ignore if there is no following statement
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181 | if (!nextToken) {
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182 | return;
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183 | }
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184 |
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185 | // Ignore if parent of node is a for variant
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186 | if (isForTypeSpecifier(node.parent.type)) {
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187 | return;
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188 | }
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189 |
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190 | // Ignore if parent of node is an export specifier
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191 | if (isExportSpecifier(node.parent.type)) {
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192 | return;
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193 | }
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194 |
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195 | /*
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196 | * Some coding styles use multiple `var` statements, so do nothing if
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197 | * the next token is a `var` statement.
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198 | */
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199 | if (nextToken.type === "Keyword" && isVar(nextToken.value)) {
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200 | return;
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201 | }
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202 |
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203 | // Ignore if it is last statement in a block
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204 | if (isLastNode(node)) {
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205 | return;
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206 | }
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207 |
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208 | // Next statement is not a `var`...
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209 | const noNextLineToken = nextToken.loc.start.line > nextLineNum;
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210 | const hasNextLineComment = (typeof commentEndLine[nextLineNum] !== "undefined");
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211 |
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212 | if (mode === "never" && noNextLineToken && !hasNextLineComment) {
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213 | context.report({
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214 | node,
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215 | messageId: "unexpected",
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216 | data: { identifier: node.name },
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217 | fix(fixer) {
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218 | const linesBetween = sourceCode.getText().slice(lastToken.range[1], nextToken.range[0]).split(astUtils.LINEBREAK_MATCHER);
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219 |
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220 | return fixer.replaceTextRange([lastToken.range[1], nextToken.range[0]], `${linesBetween.slice(0, -1).join("")}\n${linesBetween[linesBetween.length - 1]}`);
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221 | }
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222 | });
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223 | }
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224 |
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225 | // Token on the next line, or comment without blank line
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226 | if (
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227 | mode === "always" && (
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228 | !noNextLineToken ||
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229 | hasNextLineComment && !hasBlankLineAfterComment(nextToken, nextLineNum)
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230 | )
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231 | ) {
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232 | context.report({
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233 | node,
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234 | messageId: "expected",
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235 | data: { identifier: node.name },
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236 | fix(fixer) {
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237 | if ((noNextLineToken ? getLastCommentLineOfBlock(nextLineNum) : lastToken.loc.end.line) === nextToken.loc.start.line) {
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238 | return fixer.insertTextBefore(nextToken, "\n\n");
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239 | }
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240 |
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241 | return fixer.insertTextBeforeRange([nextToken.range[0] - nextToken.loc.start.column, nextToken.range[1]], "\n");
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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 | //--------------------------------------------------------------------------
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248 | // Public
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249 | //--------------------------------------------------------------------------
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250 |
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251 | return {
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252 | VariableDeclaration: checkForBlankLine
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253 | };
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254 |
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255 | }
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256 | };
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