254 lines
9.5 KiB
JavaScript
254 lines
9.5 KiB
JavaScript
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/**
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* @fileoverview Rule to check empty newline after "var" statement
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* @author Gopal Venkatesan
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* @deprecated in ESLint v4.0.0
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Requirements
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//------------------------------------------------------------------------------
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const astUtils = require("./utils/ast-utils");
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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/** @type {import('../shared/types').Rule} */
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module.exports = {
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meta: {
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type: "layout",
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docs: {
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description: "Require or disallow an empty line after variable declarations",
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recommended: false,
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url: "https://eslint.org/docs/latest/rules/newline-after-var"
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},
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schema: [
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{
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enum: ["never", "always"]
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}
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],
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fixable: "whitespace",
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messages: {
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expected: "Expected blank line after variable declarations.",
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unexpected: "Unexpected blank line after variable declarations."
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},
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deprecated: true,
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replacedBy: ["padding-line-between-statements"]
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},
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create(context) {
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const sourceCode = context.sourceCode;
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// Default `mode` to "always".
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const mode = context.options[0] === "never" ? "never" : "always";
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// Cache starting and ending line numbers of comments for faster lookup
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const commentEndLine = sourceCode.getAllComments().reduce((result, token) => {
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result[token.loc.start.line] = token.loc.end.line;
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return result;
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}, {});
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//--------------------------------------------------------------------------
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// Helpers
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//--------------------------------------------------------------------------
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/**
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* Gets a token from the given node to compare line to the next statement.
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*
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* 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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*
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* - The last token is semicolon.
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* - The semicolon is on a different line from the previous token of the semicolon.
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*
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* This behavior would address semicolon-less style code. e.g.:
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*
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* var foo = 1
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*
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* ;(a || b).doSomething()
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* @param {ASTNode} node The node to get.
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* @returns {Token} The token to compare line to the next statement.
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*/
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function getLastToken(node) {
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const lastToken = sourceCode.getLastToken(node);
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if (lastToken.type === "Punctuator" && lastToken.value === ";") {
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const prevToken = sourceCode.getTokenBefore(lastToken);
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if (prevToken.loc.end.line !== lastToken.loc.start.line) {
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return prevToken;
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}
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}
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return lastToken;
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}
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/**
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* Determine if provided keyword is a variable declaration
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* @private
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* @param {string} keyword keyword to test
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* @returns {boolean} True if `keyword` is a type of var
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*/
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function isVar(keyword) {
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return keyword === "var" || keyword === "let" || keyword === "const";
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}
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/**
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* Determine if provided keyword is a variant of for specifiers
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* @private
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* @param {string} keyword keyword to test
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* @returns {boolean} True if `keyword` is a variant of for specifier
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*/
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function isForTypeSpecifier(keyword) {
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return keyword === "ForStatement" || keyword === "ForInStatement" || keyword === "ForOfStatement";
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}
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/**
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* Determine if provided keyword is an export specifiers
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* @private
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* @param {string} nodeType nodeType to test
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* @returns {boolean} True if `nodeType` is an export specifier
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*/
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function isExportSpecifier(nodeType) {
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return nodeType === "ExportNamedDeclaration" || nodeType === "ExportSpecifier" ||
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nodeType === "ExportDefaultDeclaration" || nodeType === "ExportAllDeclaration";
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}
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/**
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* Determine if provided node is the last of their parent block.
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* @private
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* @param {ASTNode} node node to test
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* @returns {boolean} True if `node` is last of their parent block.
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*/
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function isLastNode(node) {
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const token = sourceCode.getTokenAfter(node);
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return !token || (token.type === "Punctuator" && token.value === "}");
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}
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/**
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* Gets the last line of a group of consecutive comments
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* @param {number} commentStartLine The starting line of the group
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* @returns {number} The number of the last comment line of the group
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*/
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function getLastCommentLineOfBlock(commentStartLine) {
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const currentCommentEnd = commentEndLine[commentStartLine];
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return commentEndLine[currentCommentEnd + 1] ? getLastCommentLineOfBlock(currentCommentEnd + 1) : currentCommentEnd;
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}
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/**
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* Determine if a token starts more than one line after a comment ends
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* @param {token} token The token being checked
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* @param {integer} commentStartLine The line number on which the comment starts
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* @returns {boolean} True if `token` does not start immediately after a comment
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*/
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function hasBlankLineAfterComment(token, commentStartLine) {
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return token.loc.start.line > getLastCommentLineOfBlock(commentStartLine) + 1;
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}
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/**
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* Checks that a blank line exists after a variable declaration when mode is
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* set to "always", or checks that there is no blank line when mode is set
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* to "never"
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* @private
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* @param {ASTNode} node `VariableDeclaration` node to test
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* @returns {void}
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*/
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function checkForBlankLine(node) {
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/*
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* 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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* sometimes be second-last if there is a semicolon on a different line.
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*/
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const lastToken = getLastToken(node),
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/*
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* If lastToken is the last token of the node, nextToken should be the token after the node. Otherwise, nextToken
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* is the last token of the node.
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*/
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nextToken = lastToken === sourceCode.getLastToken(node) ? sourceCode.getTokenAfter(node) : sourceCode.getLastToken(node),
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nextLineNum = lastToken.loc.end.line + 1;
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// Ignore if there is no following statement
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if (!nextToken) {
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return;
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}
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// Ignore if parent of node is a for variant
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if (isForTypeSpecifier(node.parent.type)) {
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return;
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}
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// Ignore if parent of node is an export specifier
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if (isExportSpecifier(node.parent.type)) {
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return;
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}
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/*
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* Some coding styles use multiple `var` statements, so do nothing if
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* the next token is a `var` statement.
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*/
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if (nextToken.type === "Keyword" && isVar(nextToken.value)) {
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return;
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}
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// Ignore if it is last statement in a block
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if (isLastNode(node)) {
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return;
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}
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// Next statement is not a `var`...
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const noNextLineToken = nextToken.loc.start.line > nextLineNum;
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const hasNextLineComment = (typeof commentEndLine[nextLineNum] !== "undefined");
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if (mode === "never" && noNextLineToken && !hasNextLineComment) {
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context.report({
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node,
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messageId: "unexpected",
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fix(fixer) {
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const linesBetween = sourceCode.getText().slice(lastToken.range[1], nextToken.range[0]).split(astUtils.LINEBREAK_MATCHER);
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return fixer.replaceTextRange([lastToken.range[1], nextToken.range[0]], `${linesBetween.slice(0, -1).join("")}\n${linesBetween[linesBetween.length - 1]}`);
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}
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});
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}
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// Token on the next line, or comment without blank line
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if (
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mode === "always" && (
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!noNextLineToken ||
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hasNextLineComment && !hasBlankLineAfterComment(nextToken, nextLineNum)
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)
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) {
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context.report({
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node,
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messageId: "expected",
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fix(fixer) {
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if ((noNextLineToken ? getLastCommentLineOfBlock(nextLineNum) : lastToken.loc.end.line) === nextToken.loc.start.line) {
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return fixer.insertTextBefore(nextToken, "\n\n");
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}
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return fixer.insertTextBeforeRange([nextToken.range[0] - nextToken.loc.start.column, nextToken.range[1]], "\n");
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}
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});
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}
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}
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//--------------------------------------------------------------------------
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// Public
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//--------------------------------------------------------------------------
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return {
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VariableDeclaration: checkForBlankLine
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};
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}
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};
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