/** * @fileoverview Rule to check empty newline after "var" statement * @author Gopal Venkatesan * @deprecated in ESLint v4.0.0 */ "use strict"; //------------------------------------------------------------------------------ // Requirements //------------------------------------------------------------------------------ const astUtils = require("./utils/ast-utils"); //------------------------------------------------------------------------------ // Rule Definition //------------------------------------------------------------------------------ /** @type {import('../types').Rule.RuleModule} */ module.exports = { meta: { type: "layout", docs: { description: "Require or disallow an empty line after variable declarations", recommended: false, url: "https://eslint.org/docs/latest/rules/newline-after-var", }, schema: [ { enum: ["never", "always"], }, ], fixable: "whitespace", messages: { expected: "Expected blank line after variable declarations.", unexpected: "Unexpected blank line after variable declarations.", }, deprecated: { message: "The rule was replaced with a more general rule.", url: "https://eslint.org/blog/2017/06/eslint-v4.0.0-released/", deprecatedSince: "4.0.0", availableUntil: null, replacedBy: [ { message: "The new rule moved to a plugin.", url: "https://eslint.org/docs/latest/rules/padding-line-between-statements#examples", plugin: { name: "@stylistic/eslint-plugin-js", url: "https://eslint.style/packages/js", }, rule: { name: "padding-line-between-statements", url: "https://eslint.style/rules/js/padding-line-between-statements", }, }, ], }, }, create(context) { const sourceCode = context.sourceCode; // Default `mode` to "always". const mode = context.options[0] === "never" ? "never" : "always"; // Cache starting and ending line numbers of comments for faster lookup const commentEndLine = sourceCode .getAllComments() .reduce((result, token) => { result[token.loc.start.line] = token.loc.end.line; return result; }, {}); //-------------------------------------------------------------------------- // Helpers //-------------------------------------------------------------------------- /** * Gets a token from the given node to compare line to the next statement. * * In general, the token is the last token of the node. However, the token is the second last token if the following conditions satisfy. * * - The last token is semicolon. * - The semicolon is on a different line from the previous token of the semicolon. * * This behavior would address semicolon-less style code. e.g.: * * var foo = 1 * * ;(a || b).doSomething() * @param {ASTNode} node The node to get. * @returns {Token} The token to compare line to the next statement. */ function getLastToken(node) { const lastToken = sourceCode.getLastToken(node); if (lastToken.type === "Punctuator" && lastToken.value === ";") { const prevToken = sourceCode.getTokenBefore(lastToken); if (prevToken.loc.end.line !== lastToken.loc.start.line) { return prevToken; } } return lastToken; } /** * Determine if provided keyword is a variable declaration * @private * @param {string} keyword keyword to test * @returns {boolean} True if `keyword` is a type of var */ function isVar(keyword) { return ( keyword === "var" || keyword === "let" || keyword === "const" ); } /** * Determine if provided keyword is a variant of for specifiers * @private * @param {string} keyword keyword to test * @returns {boolean} True if `keyword` is a variant of for specifier */ function isForTypeSpecifier(keyword) { return ( keyword === "ForStatement" || keyword === "ForInStatement" || keyword === "ForOfStatement" ); } /** * Determine if provided keyword is an export specifiers * @private * @param {string} nodeType nodeType to test * @returns {boolean} True if `nodeType` is an export specifier */ function isExportSpecifier(nodeType) { return ( nodeType === "ExportNamedDeclaration" || nodeType === "ExportSpecifier" || nodeType === "ExportDefaultDeclaration" || nodeType === "ExportAllDeclaration" ); } /** * Determine if provided node is the last of their parent block. * @private * @param {ASTNode} node node to test * @returns {boolean} True if `node` is last of their parent block. */ function isLastNode(node) { const token = sourceCode.getTokenAfter(node); return ( !token || (token.type === "Punctuator" && token.value === "}") ); } /** * Gets the last line of a group of consecutive comments * @param {number} commentStartLine The starting line of the group * @returns {number} The number of the last comment line of the group */ function getLastCommentLineOfBlock(commentStartLine) { const currentCommentEnd = commentEndLine[commentStartLine]; return commentEndLine[currentCommentEnd + 1] ? getLastCommentLineOfBlock(currentCommentEnd + 1) : currentCommentEnd; } /** * Determine if a token starts more than one line after a comment ends * @param {token} token The token being checked * @param {integer} commentStartLine The line number on which the comment starts * @returns {boolean} True if `token` does not start immediately after a comment */ function hasBlankLineAfterComment(token, commentStartLine) { return ( token.loc.start.line > getLastCommentLineOfBlock(commentStartLine) + 1 ); } /** * Checks that a blank line exists after a variable declaration when mode is * set to "always", or checks that there is no blank line when mode is set * to "never" * @private * @param {ASTNode} node `VariableDeclaration` node to test * @returns {void} */ function checkForBlankLine(node) { /* * lastToken is the last token on the node's line. It will usually also be the last token of the node, but it will * sometimes be second-last if there is a semicolon on a different line. */ const lastToken = getLastToken(node), /* * If lastToken is the last token of the node, nextToken should be the token after the node. Otherwise, nextToken * is the last token of the node. */ nextToken = lastToken === sourceCode.getLastToken(node) ? sourceCode.getTokenAfter(node) : sourceCode.getLastToken(node), nextLineNum = lastToken.loc.end.line + 1; // Ignore if there is no following statement if (!nextToken) { return; } // Ignore if parent of node is a for variant if (isForTypeSpecifier(node.parent.type)) { return; } // Ignore if parent of node is an export specifier if (isExportSpecifier(node.parent.type)) { return; } /* * Some coding styles use multiple `var` statements, so do nothing if * the next token is a `var` statement. */ if (nextToken.type === "Keyword" && isVar(nextToken.value)) { return; } // Ignore if it is last statement in a block if (isLastNode(node)) { return; } // Next statement is not a `var`... const noNextLineToken = nextToken.loc.start.line > nextLineNum; const hasNextLineComment = typeof commentEndLine[nextLineNum] !== "undefined"; if (mode === "never" && noNextLineToken && !hasNextLineComment) { context.report({ node, messageId: "unexpected", fix(fixer) { const linesBetween = sourceCode .getText() .slice(lastToken.range[1], nextToken.range[0]) .split(astUtils.LINEBREAK_MATCHER); return fixer.replaceTextRange( [lastToken.range[1], nextToken.range[0]], `${linesBetween.slice(0, -1).join("")}\n${linesBetween.at(-1)}`, ); }, }); } // Token on the next line, or comment without blank line if ( mode === "always" && (!noNextLineToken || (hasNextLineComment && !hasBlankLineAfterComment(nextToken, nextLineNum))) ) { context.report({ node, messageId: "expected", fix(fixer) { if ( (noNextLineToken ? getLastCommentLineOfBlock(nextLineNum) : lastToken.loc.end.line) === nextToken.loc.start.line ) { return fixer.insertTextBefore(nextToken, "\n\n"); } return fixer.insertTextBeforeRange( [ nextToken.range[0] - nextToken.loc.start.column, nextToken.range[1], ], "\n", ); }, }); } } //-------------------------------------------------------------------------- // Public //-------------------------------------------------------------------------- return { VariableDeclaration: checkForBlankLine, }; }, };