590 lines
18 KiB
JavaScript
590 lines
18 KiB
JavaScript
/**
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* @fileoverview Rule to require or disallow newlines between statements
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* @author Toru Nagashima
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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("../ast-utils");
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//------------------------------------------------------------------------------
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// Helpers
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//------------------------------------------------------------------------------
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const LT = `[${Array.from(astUtils.LINEBREAKS).join("")}]`;
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const PADDING_LINE_SEQUENCE = new RegExp(
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String.raw`^(\s*?${LT})\s*${LT}(\s*;?)$`
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);
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const CJS_EXPORT = /^(?:module\s*\.\s*)?exports(?:\s*\.|\s*\[|$)/;
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const CJS_IMPORT = /^require\(/;
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/**
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* Creates tester which check if a node starts with specific keyword.
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*
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* @param {string} keyword The keyword to test.
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* @returns {Object} the created tester.
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* @private
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*/
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function newKeywordTester(keyword) {
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return {
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test: (node, sourceCode) =>
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sourceCode.getFirstToken(node).value === keyword
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};
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}
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/**
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* Creates tester which check if a node is specific type.
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*
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* @param {string} type The node type to test.
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* @returns {Object} the created tester.
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* @private
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*/
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function newNodeTypeTester(type) {
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return {
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test: node =>
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node.type === type
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};
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}
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/**
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* Checks the given node is an expression statement of IIFE.
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*
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* @param {ASTNode} node The node to check.
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* @returns {boolean} `true` if the node is an expression statement of IIFE.
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* @private
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*/
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function isIIFEStatement(node) {
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if (node.type === "ExpressionStatement") {
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let call = node.expression;
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if (call.type === "UnaryExpression") {
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call = call.argument;
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}
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return call.type === "CallExpression" && astUtils.isFunction(call.callee);
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}
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return false;
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}
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/**
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* Checks whether the given node is a block-like statement.
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* This checks the last token of the node is the closing brace of a block.
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*
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* @param {SourceCode} sourceCode The source code to get tokens.
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* @param {ASTNode} node The node to check.
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* @returns {boolean} `true` if the node is a block-like statement.
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* @private
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*/
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function isBlockLikeStatement(sourceCode, node) {
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// do-while with a block is a block-like statement.
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if (node.type === "DoWhileStatement" && node.body.type === "BlockStatement") {
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return true;
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}
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/*
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* IIFE is a block-like statement specially from
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* JSCS#disallowPaddingNewLinesAfterBlocks.
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*/
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if (isIIFEStatement(node)) {
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return true;
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}
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// Checks the last token is a closing brace of blocks.
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const lastToken = sourceCode.getLastToken(node, astUtils.isNotSemicolonToken);
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const belongingNode = lastToken && astUtils.isClosingBraceToken(lastToken)
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? sourceCode.getNodeByRangeIndex(lastToken.range[0])
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: null;
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return Boolean(belongingNode) && (
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belongingNode.type === "BlockStatement" ||
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belongingNode.type === "SwitchStatement"
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);
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}
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/**
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* Check whether the given node is a directive or not.
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* @param {ASTNode} node The node to check.
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* @param {SourceCode} sourceCode The source code object to get tokens.
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* @returns {boolean} `true` if the node is a directive.
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*/
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function isDirective(node, sourceCode) {
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return (
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node.type === "ExpressionStatement" &&
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(
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node.parent.type === "Program" ||
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(
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node.parent.type === "BlockStatement" &&
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astUtils.isFunction(node.parent.parent)
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)
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) &&
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node.expression.type === "Literal" &&
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typeof node.expression.value === "string" &&
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!astUtils.isParenthesised(sourceCode, node.expression)
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);
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}
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/**
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* Check whether the given node is a part of directive prologue or not.
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* @param {ASTNode} node The node to check.
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* @param {SourceCode} sourceCode The source code object to get tokens.
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* @returns {boolean} `true` if the node is a part of directive prologue.
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*/
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function isDirectivePrologue(node, sourceCode) {
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if (isDirective(node, sourceCode)) {
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for (const sibling of node.parent.body) {
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if (sibling === node) {
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break;
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}
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if (!isDirective(sibling, sourceCode)) {
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return false;
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}
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}
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return true;
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}
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return false;
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}
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/**
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* Gets the actual last token.
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*
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* If a semicolon is semicolon-less style's semicolon, this ignores it.
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* For example:
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*
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* foo()
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* ;[1, 2, 3].forEach(bar)
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*
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* @param {SourceCode} sourceCode The source code to get tokens.
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* @param {ASTNode} node The node to get.
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* @returns {Token} The actual last token.
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* @private
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*/
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function getActualLastToken(sourceCode, node) {
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const semiToken = sourceCode.getLastToken(node);
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const prevToken = sourceCode.getTokenBefore(semiToken);
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const nextToken = sourceCode.getTokenAfter(semiToken);
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const isSemicolonLessStyle = Boolean(
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prevToken &&
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nextToken &&
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prevToken.range[0] >= node.range[0] &&
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astUtils.isSemicolonToken(semiToken) &&
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semiToken.loc.start.line !== prevToken.loc.end.line &&
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semiToken.loc.end.line === nextToken.loc.start.line
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);
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return isSemicolonLessStyle ? prevToken : semiToken;
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}
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/**
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* This returns the concatenation of the first 2 captured strings.
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* @param {string} _ Unused. Whole matched string.
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* @param {string} trailingSpaces The trailing spaces of the first line.
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* @param {string} indentSpaces The indentation spaces of the last line.
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* @returns {string} The concatenation of trailingSpaces and indentSpaces.
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* @private
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*/
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function replacerToRemovePaddingLines(_, trailingSpaces, indentSpaces) {
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return trailingSpaces + indentSpaces;
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}
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/**
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* Check and report statements for `any` configuration.
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* It does nothing.
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*
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* @returns {void}
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* @private
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*/
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function verifyForAny() {
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}
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/**
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* Check and report statements for `never` configuration.
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* This autofix removes blank lines between the given 2 statements.
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* However, if comments exist between 2 blank lines, it does not remove those
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* blank lines automatically.
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*
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* @param {RuleContext} context The rule context to report.
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* @param {ASTNode} _ Unused. The previous node to check.
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* @param {ASTNode} nextNode The next node to check.
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* @param {Array<Token[]>} paddingLines The array of token pairs that blank
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* lines exist between the pair.
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* @returns {void}
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* @private
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*/
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function verifyForNever(context, _, nextNode, paddingLines) {
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if (paddingLines.length === 0) {
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return;
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}
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context.report({
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node: nextNode,
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message: "Unexpected blank line before this statement.",
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fix(fixer) {
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if (paddingLines.length >= 2) {
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return null;
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}
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const prevToken = paddingLines[0][0];
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const nextToken = paddingLines[0][1];
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const start = prevToken.range[1];
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const end = nextToken.range[0];
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const text = context.getSourceCode().text
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.slice(start, end)
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.replace(PADDING_LINE_SEQUENCE, replacerToRemovePaddingLines);
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return fixer.replaceTextRange([start, end], text);
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}
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});
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}
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/**
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* Check and report statements for `always` configuration.
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* This autofix inserts a blank line between the given 2 statements.
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* If the `prevNode` has trailing comments, it inserts a blank line after the
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* trailing comments.
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*
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* @param {RuleContext} context The rule context to report.
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* @param {ASTNode} prevNode The previous node to check.
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* @param {ASTNode} nextNode The next node to check.
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* @param {Array<Token[]>} paddingLines The array of token pairs that blank
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* lines exist between the pair.
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* @returns {void}
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* @private
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*/
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function verifyForAlways(context, prevNode, nextNode, paddingLines) {
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if (paddingLines.length > 0) {
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return;
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}
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context.report({
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node: nextNode,
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message: "Expected blank line before this statement.",
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fix(fixer) {
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const sourceCode = context.getSourceCode();
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let prevToken = getActualLastToken(sourceCode, prevNode);
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const nextToken = sourceCode.getFirstTokenBetween(
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prevToken,
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nextNode,
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{
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includeComments: true,
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/**
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* Skip the trailing comments of the previous node.
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* This inserts a blank line after the last trailing comment.
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*
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* For example:
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*
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* foo(); // trailing comment.
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* // comment.
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* bar();
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*
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* Get fixed to:
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*
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* foo(); // trailing comment.
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*
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* // comment.
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* bar();
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*
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* @param {Token} token The token to check.
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* @returns {boolean} `true` if the token is not a trailing comment.
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* @private
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*/
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filter(token) {
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if (astUtils.isTokenOnSameLine(prevToken, token)) {
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prevToken = token;
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return false;
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}
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return true;
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}
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}
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) || nextNode;
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const insertText = astUtils.isTokenOnSameLine(prevToken, nextToken)
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? "\n\n"
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: "\n";
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return fixer.insertTextAfter(prevToken, insertText);
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}
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});
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}
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/**
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* Types of blank lines.
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* `any`, `never`, and `always` are defined.
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* Those have `verify` method to check and report statements.
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* @private
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*/
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const PaddingTypes = {
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any: { verify: verifyForAny },
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never: { verify: verifyForNever },
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always: { verify: verifyForAlways }
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};
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/**
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* Types of statements.
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* Those have `test` method to check it matches to the given statement.
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* @private
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*/
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const StatementTypes = {
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"*": { test: () => true },
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"block-like": {
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test: (node, sourceCode) => isBlockLikeStatement(sourceCode, node)
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},
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"cjs-export": {
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test: (node, sourceCode) =>
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node.type === "ExpressionStatement" &&
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node.expression.type === "AssignmentExpression" &&
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CJS_EXPORT.test(sourceCode.getText(node.expression.left))
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},
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"cjs-import": {
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test: (node, sourceCode) =>
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node.type === "VariableDeclaration" &&
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node.declarations.length > 0 &&
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Boolean(node.declarations[0].init) &&
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CJS_IMPORT.test(sourceCode.getText(node.declarations[0].init))
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},
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directive: {
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test: isDirectivePrologue
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},
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expression: {
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test: (node, sourceCode) =>
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node.type === "ExpressionStatement" &&
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!isDirectivePrologue(node, sourceCode)
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},
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"multiline-block-like": {
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test: (node, sourceCode) =>
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node.loc.start.line !== node.loc.end.line &&
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isBlockLikeStatement(sourceCode, node)
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},
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block: newNodeTypeTester("BlockStatement"),
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empty: newNodeTypeTester("EmptyStatement"),
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break: newKeywordTester("break"),
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case: newKeywordTester("case"),
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class: newKeywordTester("class"),
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const: newKeywordTester("const"),
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continue: newKeywordTester("continue"),
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debugger: newKeywordTester("debugger"),
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default: newKeywordTester("default"),
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do: newKeywordTester("do"),
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export: newKeywordTester("export"),
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for: newKeywordTester("for"),
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function: newKeywordTester("function"),
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if: newKeywordTester("if"),
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import: newKeywordTester("import"),
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let: newKeywordTester("let"),
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return: newKeywordTester("return"),
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switch: newKeywordTester("switch"),
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throw: newKeywordTester("throw"),
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try: newKeywordTester("try"),
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var: newKeywordTester("var"),
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while: newKeywordTester("while"),
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with: newKeywordTester("with")
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};
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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module.exports = {
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meta: {
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docs: {
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description: "require or disallow padding lines between statements",
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category: "Stylistic Issues",
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recommended: false
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},
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fixable: "whitespace",
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schema: {
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definitions: {
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paddingType: {
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enum: Object.keys(PaddingTypes)
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},
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statementType: {
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anyOf: [
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{ enum: Object.keys(StatementTypes) },
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{
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type: "array",
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items: { enum: Object.keys(StatementTypes) },
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minItems: 1,
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uniqueItems: true,
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additionalItems: false
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}
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]
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}
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},
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type: "array",
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items: {
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type: "object",
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properties: {
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blankLine: { $ref: "#/definitions/paddingType" },
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prev: { $ref: "#/definitions/statementType" },
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next: { $ref: "#/definitions/statementType" }
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},
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additionalProperties: false,
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required: ["blankLine", "prev", "next"]
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},
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additionalItems: false
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}
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},
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create(context) {
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const sourceCode = context.getSourceCode();
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const configureList = context.options || [];
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let scopeInfo = null;
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/**
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* Processes to enter to new scope.
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* This manages the current previous statement.
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* @returns {void}
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* @private
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*/
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function enterScope() {
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scopeInfo = {
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upper: scopeInfo,
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prevNode: null
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};
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}
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/**
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* Processes to exit from the current scope.
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* @returns {void}
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* @private
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*/
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function exitScope() {
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scopeInfo = scopeInfo.upper;
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}
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/**
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* Checks whether the given node matches the given type.
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*
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* @param {ASTNode} node The statement node to check.
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* @param {string|string[]} type The statement type to check.
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* @returns {boolean} `true` if the statement node matched the type.
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* @private
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*/
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function match(node, type) {
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while (node.type === "LabeledStatement") {
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node = node.body;
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}
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if (Array.isArray(type)) {
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return type.some(match.bind(null, node));
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}
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return StatementTypes[type].test(node, sourceCode);
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}
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/**
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* Finds the last matched configure from configureList.
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*
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* @param {ASTNode} prevNode The previous statement to match.
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* @param {ASTNode} nextNode The current statement to match.
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* @returns {Object} The tester of the last matched configure.
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* @private
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*/
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function getPaddingType(prevNode, nextNode) {
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for (let i = configureList.length - 1; i >= 0; --i) {
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const configure = configureList[i];
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const matched =
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match(prevNode, configure.prev) &&
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match(nextNode, configure.next);
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if (matched) {
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return PaddingTypes[configure.blankLine];
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}
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}
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return PaddingTypes.any;
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}
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/**
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* Gets padding line sequences between the given 2 statements.
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* Comments are separators of the padding line sequences.
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*
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* @param {ASTNode} prevNode The previous statement to count.
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* @param {ASTNode} nextNode The current statement to count.
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* @returns {Array<Token[]>} The array of token pairs.
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* @private
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*/
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function getPaddingLineSequences(prevNode, nextNode) {
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const pairs = [];
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let prevToken = getActualLastToken(sourceCode, prevNode);
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if (nextNode.loc.start.line - prevToken.loc.end.line >= 2) {
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do {
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const token = sourceCode.getTokenAfter(
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prevToken,
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{ includeComments: true }
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);
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if (token.loc.start.line - prevToken.loc.end.line >= 2) {
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pairs.push([prevToken, token]);
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}
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prevToken = token;
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} while (prevToken.range[0] < nextNode.range[0]);
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}
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return pairs;
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}
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/**
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* Verify padding lines between the given node and the previous node.
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*
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* @param {ASTNode} node The node to verify.
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* @returns {void}
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* @private
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*/
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function verify(node) {
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const parentType = node.parent.type;
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const validParent =
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astUtils.STATEMENT_LIST_PARENTS.has(parentType) ||
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parentType === "SwitchStatement";
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if (!validParent) {
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return;
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}
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// Save this node as the current previous statement.
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const prevNode = scopeInfo.prevNode;
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// Verify.
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if (prevNode) {
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const type = getPaddingType(prevNode, node);
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const paddingLines = getPaddingLineSequences(prevNode, node);
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type.verify(context, prevNode, node, paddingLines);
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}
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scopeInfo.prevNode = node;
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}
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/**
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* Verify padding lines between the given node and the previous node.
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* Then process to enter to new scope.
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*
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* @param {ASTNode} node The node to verify.
|
|
* @returns {void}
|
|
* @private
|
|
*/
|
|
function verifyThenEnterScope(node) {
|
|
verify(node);
|
|
enterScope();
|
|
}
|
|
|
|
return {
|
|
Program: enterScope,
|
|
BlockStatement: enterScope,
|
|
SwitchStatement: enterScope,
|
|
"Program:exit": exitScope,
|
|
"BlockStatement:exit": exitScope,
|
|
"SwitchStatement:exit": exitScope,
|
|
|
|
":statement": verify,
|
|
|
|
SwitchCase: verifyThenEnterScope,
|
|
"SwitchCase:exit": exitScope
|
|
};
|
|
}
|
|
};
|