/**
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* @fileoverview A rule to ensure whitespace before 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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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: "enforce consistent spacing before blocks",
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category: "Stylistic Issues",
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recommended: false,
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url: "https://eslint.org/docs/rules/space-before-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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keywords: {
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enum: ["always", "never", "off"]
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},
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functions: {
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enum: ["always", "never", "off"]
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},
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classes: {
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enum: ["always", "never", "off"]
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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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}
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]
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},
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create(context) {
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const config = context.options[0],
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sourceCode = context.getSourceCode();
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let alwaysFunctions = true,
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alwaysKeywords = true,
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alwaysClasses = true,
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neverFunctions = false,
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neverKeywords = false,
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neverClasses = false;
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if (typeof config === "object") {
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alwaysFunctions = config.functions === "always";
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alwaysKeywords = config.keywords === "always";
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alwaysClasses = config.classes === "always";
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neverFunctions = config.functions === "never";
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neverKeywords = config.keywords === "never";
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neverClasses = config.classes === "never";
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} else if (config === "never") {
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alwaysFunctions = false;
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alwaysKeywords = false;
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alwaysClasses = false;
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neverFunctions = true;
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neverKeywords = true;
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neverClasses = true;
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}
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/**
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* Checks whether or not a given token is an arrow operator (=>) or a keyword
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* in order to avoid to conflict with `arrow-spacing` and `keyword-spacing`.
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*
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* @param {Token} token - A token to check.
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* @returns {boolean} `true` if the token is an arrow operator.
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*/
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function isConflicted(token) {
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return (token.type === "Punctuator" && token.value === "=>") || token.type === "Keyword";
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}
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/**
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* Checks the given BlockStatement node has a preceding space if it doesn’t start on a new line.
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* @param {ASTNode|Token} node The AST node of a BlockStatement.
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* @returns {void} undefined.
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*/
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function checkPrecedingSpace(node) {
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const precedingToken = sourceCode.getTokenBefore(node);
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if (precedingToken && !isConflicted(precedingToken) && astUtils.isTokenOnSameLine(precedingToken, node)) {
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const hasSpace = sourceCode.isSpaceBetweenTokens(precedingToken, node);
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const parent = context.getAncestors().pop();
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let requireSpace;
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let requireNoSpace;
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if (parent.type === "FunctionExpression" || parent.type === "FunctionDeclaration") {
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requireSpace = alwaysFunctions;
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requireNoSpace = neverFunctions;
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} else if (node.type === "ClassBody") {
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requireSpace = alwaysClasses;
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requireNoSpace = neverClasses;
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} else {
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requireSpace = alwaysKeywords;
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requireNoSpace = neverKeywords;
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}
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if (requireSpace && !hasSpace) {
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context.report({
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node,
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message: "Missing space before opening brace.",
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fix(fixer) {
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return fixer.insertTextBefore(node, " ");
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}
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});
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} else if (requireNoSpace && hasSpace) {
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context.report({
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node,
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message: "Unexpected space before opening brace.",
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fix(fixer) {
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return fixer.removeRange([precedingToken.range[1], node.range[0]]);
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}
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});
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}
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}
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}
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/**
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* Checks if the CaseBlock of an given SwitchStatement node has a preceding space.
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* @param {ASTNode} node The node of a SwitchStatement.
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* @returns {void} undefined.
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*/
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function checkSpaceBeforeCaseBlock(node) {
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const cases = node.cases;
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let openingBrace;
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if (cases.length > 0) {
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openingBrace = sourceCode.getTokenBefore(cases[0]);
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} else {
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openingBrace = sourceCode.getLastToken(node, 1);
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}
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checkPrecedingSpace(openingBrace);
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}
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return {
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BlockStatement: checkPrecedingSpace,
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ClassBody: checkPrecedingSpace,
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SwitchStatement: checkSpaceBeforeCaseBlock
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};
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}
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};
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