eslint/lib/rules/no-trailing-spaces.js

   1 /**
   2  * @fileoverview Disallow trailing spaces at the end of lines.
   3  * @author Nodeca Team <https://github.com/nodeca>
   4  */
   5 "use strict";
   6
   7 //------------------------------------------------------------------------------
   8 // Requirements
   9 //------------------------------------------------------------------------------
  10
  11 const astUtils = require("./utils/ast-utils");
  12
  13 //------------------------------------------------------------------------------
  14 // Rule Definition
  15 //------------------------------------------------------------------------------
  16
  17 module.exports = {
  18     meta: {
  19         type: "layout",
  20
  21         docs: {
  22             description: "disallow trailing whitespace at the end of lines",
  23             recommended: false,
  24             url: "https://eslint.org/docs/rules/no-trailing-spaces"
  25         },
  26
  27         fixable: "whitespace",
  28
  29         schema: [
  30             {
  31                 type: "object",
  32                 properties: {
  33                     skipBlankLines: {
  34                         type: "boolean",
  35                         default: false
  36                     },
  37                     ignoreComments: {
  38                         type: "boolean",
  39                         default: false
  40                     }
  41                 },
  42                 additionalProperties: false
  43             }
  44         ],
  45
  46         messages: {
  47             trailingSpace: "Trailing spaces not allowed."
  48         }
  49     },
  50
  51     create(context) {
  52         const sourceCode = context.getSourceCode();
  53
  54         const BLANK_CLASS = "[ \t\u00a0\u2000-\u200b\u3000]",
  55             SKIP_BLANK = `^${BLANK_CLASS}*$`,
  56             NONBLANK = `${BLANK_CLASS}+$`;
  57
  58         const options = context.options[0] || {},
  59             skipBlankLines = options.skipBlankLines || false,
  60             ignoreComments = options.ignoreComments || false;
  61
  62         /**
  63          * Report the error message
  64          * @param {ASTNode} node node to report
  65          * @param {int[]} location range information
  66          * @param {int[]} fixRange Range based on the whole program
  67          * @returns {void}
  68          */
  69         function report(node, location, fixRange) {
  70
  71             /*
  72              * Passing node is a bit dirty, because message data will contain big
  73              * text in `source`. But... who cares :) ?
  74              * One more kludge will not make worse the bloody wizardry of this
  75              * plugin.
  76              */
  77             context.report({
  78                 node,
  79                 loc: location,
  80                 messageId: "trailingSpace",
  81                 fix(fixer) {
  82                     return fixer.removeRange(fixRange);
  83                 }
  84             });
  85         }
  86
  87         /**
  88          * Given a list of comment nodes, return the line numbers for those comments.
  89          * @param {Array} comments An array of comment nodes.
  90          * @returns {number[]} An array of line numbers containing comments.
  91          */
  92         function getCommentLineNumbers(comments) {
  93             const lines = new Set();
  94
  95             comments.forEach(comment => {
  96                 const endLine = comment.type === "Block"
  97                     ? comment.loc.end.line - 1
  98                     : comment.loc.end.line;
  99
 100                 for (let i = comment.loc.start.line; i <= endLine; i++) {
 101                     lines.add(i);
 102                 }
 103             });
 104
 105             return lines;
 106         }
 107
 108         //--------------------------------------------------------------------------
 109         // Public
 110         //--------------------------------------------------------------------------
 111
 112         return {
 113
 114             Program: function checkTrailingSpaces(node) {
 115
 116                 /*
 117                  * Let's hack. Since Espree does not return whitespace nodes,
 118                  * fetch the source code and do matching via regexps.
 119                  */
 120
 121                 const re = new RegExp(NONBLANK, "u"),
 122                     skipMatch = new RegExp(SKIP_BLANK, "u"),
 123                     lines = sourceCode.lines,
 124                     linebreaks = sourceCode.getText().match(astUtils.createGlobalLinebreakMatcher()),
 125                     comments = sourceCode.getAllComments(),
 126                     commentLineNumbers = getCommentLineNumbers(comments);
 127
 128                 let totalLength = 0,
 129                     fixRange = [];
 130
 131                 for (let i = 0, ii = lines.length; i < ii; i++) {
 132                     const lineNumber = i + 1;
 133
 134                     /*
 135                      * Always add linebreak length to line length to accommodate for line break (\n or \r\n)
 136                      * Because during the fix time they also reserve one spot in the array.
 137                      * Usually linebreak length is 2 for \r\n (CRLF) and 1 for \n (LF)
 138                      */
 139                     const linebreakLength = linebreaks && linebreaks[i] ? linebreaks[i].length : 1;
 140                     const lineLength = lines[i].length + linebreakLength;
 141
 142                     const matches = re.exec(lines[i]);
 143
 144                     if (matches) {
 145                         const location = {
 146                             start: {
 147                                 line: lineNumber,
 148                                 column: matches.index
 149                             },
 150                             end: {
 151                                 line: lineNumber,
 152                                 column: lineLength - linebreakLength
 153                             }
 154                         };
 155
 156                         const rangeStart = totalLength + location.start.column;
 157                         const rangeEnd = totalLength + location.end.column;
 158                         const containingNode = sourceCode.getNodeByRangeIndex(rangeStart);
 159
 160                         if (containingNode && containingNode.type === "TemplateElement" &&
 161                           rangeStart > containingNode.parent.range[0] &&
 162                           rangeEnd < containingNode.parent.range[1]) {
 163                             totalLength += lineLength;
 164                             continue;
 165                         }
 166
 167                         /*
 168                          * If the line has only whitespace, and skipBlankLines
 169                          * is true, don't report it
 170                          */
 171                         if (skipBlankLines && skipMatch.test(lines[i])) {
 172                             totalLength += lineLength;
 173                             continue;
 174                         }
 175
 176                         fixRange = [rangeStart, rangeEnd];
 177
 178                         if (!ignoreComments || !commentLineNumbers.has(lineNumber)) {
 179                             report(node, location, fixRange);
 180                         }
 181                     }
 182
 183                     totalLength += lineLength;
 184                 }
 185             }
 186
 187         };
 188     }
 189 };