298 lines
10 KiB
JavaScript
298 lines
10 KiB
JavaScript
/**
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* @fileoverview A rule to ensure blank lines within blocks.
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* @author Mathias Schreck <https://github.com/lo1tuma>
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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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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 padding within blocks",
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category: "Stylistic Issues",
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recommended: false,
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url: "https://eslint.org/docs/rules/padded-blocks"
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},
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fixable: "whitespace",
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schema: [
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{
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oneOf: [
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{
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enum: ["always", "never"]
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},
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{
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type: "object",
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properties: {
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blocks: {
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enum: ["always", "never"]
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},
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switches: {
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enum: ["always", "never"]
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},
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classes: {
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enum: ["always", "never"]
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}
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},
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additionalProperties: false,
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minProperties: 1
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}
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]
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},
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{
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type: "object",
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properties: {
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allowSingleLineBlocks: {
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type: "boolean"
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}
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},
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additionalProperties: false
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}
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],
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messages: {
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alwaysPadBlock: "Block must be padded by blank lines.",
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neverPadBlock: "Block must not be padded by blank lines."
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}
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},
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create(context) {
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const options = {};
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const typeOptions = context.options[0] || "always";
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const exceptOptions = context.options[1] || {};
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if (typeof typeOptions === "string") {
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const shouldHavePadding = typeOptions === "always";
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options.blocks = shouldHavePadding;
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options.switches = shouldHavePadding;
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options.classes = shouldHavePadding;
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} else {
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if (Object.prototype.hasOwnProperty.call(typeOptions, "blocks")) {
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options.blocks = typeOptions.blocks === "always";
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}
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if (Object.prototype.hasOwnProperty.call(typeOptions, "switches")) {
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options.switches = typeOptions.switches === "always";
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}
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if (Object.prototype.hasOwnProperty.call(typeOptions, "classes")) {
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options.classes = typeOptions.classes === "always";
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}
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}
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if (Object.prototype.hasOwnProperty.call(exceptOptions, "allowSingleLineBlocks")) {
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options.allowSingleLineBlocks = exceptOptions.allowSingleLineBlocks === true;
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}
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const sourceCode = context.getSourceCode();
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/**
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* Gets the open brace token from a given node.
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* @param {ASTNode} node A BlockStatement or SwitchStatement node from which to get the open brace.
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* @returns {Token} The token of the open brace.
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*/
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function getOpenBrace(node) {
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if (node.type === "SwitchStatement") {
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return sourceCode.getTokenBefore(node.cases[0]);
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}
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return sourceCode.getFirstToken(node);
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}
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/**
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* Checks if the given parameter is a comment node
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* @param {ASTNode|Token} node An AST node or token
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* @returns {boolean} True if node is a comment
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*/
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function isComment(node) {
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return node.type === "Line" || node.type === "Block";
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}
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/**
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* Checks if there is padding between two tokens
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* @param {Token} first The first token
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* @param {Token} second The second token
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* @returns {boolean} True if there is at least a line between the tokens
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*/
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function isPaddingBetweenTokens(first, second) {
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return second.loc.start.line - first.loc.end.line >= 2;
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}
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/**
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* Checks if the given token has a blank line after it.
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* @param {Token} token The token to check.
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* @returns {boolean} Whether or not the token is followed by a blank line.
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*/
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function getFirstBlockToken(token) {
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let prev,
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first = token;
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do {
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prev = first;
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first = sourceCode.getTokenAfter(first, { includeComments: true });
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} while (isComment(first) && first.loc.start.line === prev.loc.end.line);
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return first;
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}
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/**
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* Checks if the given token is preceded by a blank line.
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* @param {Token} token The token to check
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* @returns {boolean} Whether or not the token is preceded by a blank line
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*/
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function getLastBlockToken(token) {
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let last = token,
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next;
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do {
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next = last;
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last = sourceCode.getTokenBefore(last, { includeComments: true });
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} while (isComment(last) && last.loc.end.line === next.loc.start.line);
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return last;
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}
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/**
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* Checks if a node should be padded, according to the rule config.
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* @param {ASTNode} node The AST node to check.
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* @returns {boolean} True if the node should be padded, false otherwise.
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*/
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function requirePaddingFor(node) {
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switch (node.type) {
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case "BlockStatement":
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return options.blocks;
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case "SwitchStatement":
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return options.switches;
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case "ClassBody":
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return options.classes;
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/* istanbul ignore next */
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default:
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throw new Error("unreachable");
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}
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}
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/**
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* Checks the given BlockStatement node to be padded if the block is not empty.
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* @param {ASTNode} node The AST node of a BlockStatement.
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* @returns {void} undefined.
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*/
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function checkPadding(node) {
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const openBrace = getOpenBrace(node),
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firstBlockToken = getFirstBlockToken(openBrace),
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tokenBeforeFirst = sourceCode.getTokenBefore(firstBlockToken, { includeComments: true }),
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closeBrace = sourceCode.getLastToken(node),
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lastBlockToken = getLastBlockToken(closeBrace),
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tokenAfterLast = sourceCode.getTokenAfter(lastBlockToken, { includeComments: true }),
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blockHasTopPadding = isPaddingBetweenTokens(tokenBeforeFirst, firstBlockToken),
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blockHasBottomPadding = isPaddingBetweenTokens(lastBlockToken, tokenAfterLast);
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if (options.allowSingleLineBlocks && astUtils.isTokenOnSameLine(tokenBeforeFirst, tokenAfterLast)) {
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return;
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}
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if (requirePaddingFor(node)) {
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if (!blockHasTopPadding) {
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context.report({
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node,
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loc: {
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start: tokenBeforeFirst.loc.start,
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end: firstBlockToken.loc.start
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},
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fix(fixer) {
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return fixer.insertTextAfter(tokenBeforeFirst, "\n");
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},
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messageId: "alwaysPadBlock"
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});
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}
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if (!blockHasBottomPadding) {
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context.report({
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node,
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loc: {
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end: tokenAfterLast.loc.start,
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start: lastBlockToken.loc.end
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},
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fix(fixer) {
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return fixer.insertTextBefore(tokenAfterLast, "\n");
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},
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messageId: "alwaysPadBlock"
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});
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}
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} else {
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if (blockHasTopPadding) {
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context.report({
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node,
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loc: {
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start: tokenBeforeFirst.loc.start,
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end: firstBlockToken.loc.start
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},
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fix(fixer) {
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return fixer.replaceTextRange([tokenBeforeFirst.range[1], firstBlockToken.range[0] - firstBlockToken.loc.start.column], "\n");
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},
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messageId: "neverPadBlock"
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});
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}
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if (blockHasBottomPadding) {
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context.report({
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node,
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loc: {
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end: tokenAfterLast.loc.start,
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start: lastBlockToken.loc.end
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},
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messageId: "neverPadBlock",
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fix(fixer) {
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return fixer.replaceTextRange([lastBlockToken.range[1], tokenAfterLast.range[0] - tokenAfterLast.loc.start.column], "\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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const rule = {};
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if (Object.prototype.hasOwnProperty.call(options, "switches")) {
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rule.SwitchStatement = function(node) {
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if (node.cases.length === 0) {
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return;
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}
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checkPadding(node);
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};
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}
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if (Object.prototype.hasOwnProperty.call(options, "blocks")) {
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rule.BlockStatement = function(node) {
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if (node.body.length === 0) {
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return;
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}
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checkPadding(node);
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};
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}
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if (Object.prototype.hasOwnProperty.call(options, "classes")) {
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rule.ClassBody = function(node) {
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if (node.body.length === 0) {
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return;
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}
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checkPadding(node);
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};
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}
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return rule;
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}
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};
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