rest-spread-spacing.js

   1 /**
   2  * @fileoverview Enforce spacing between rest and spread operators and their expressions.
   3  * @author Kai Cataldo
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Rule Definition
  10 //------------------------------------------------------------------------------
  11
  12 module.exports = {
  13     meta: {
  14         type: "layout",
  15
  16         docs: {
  17             description: "enforce spacing between rest and spread operators and their expressions",
  18             category: "ECMAScript 6",
  19             recommended: false,
  20             url: "https://eslint.org/docs/rules/rest-spread-spacing"
  21         },
  22
  23         fixable: "whitespace",
  24
  25         schema: [
  26             {
  27                 enum: ["always", "never"]
  28             }
  29         ]
  30     },
  31
  32     create(context) {
  33         const sourceCode = context.getSourceCode(),
  34             alwaysSpace = context.options[0] === "always";
  35
  36         //--------------------------------------------------------------------------
  37         // Helpers
  38         //--------------------------------------------------------------------------
  39
  40         /**
  41          * Checks whitespace between rest/spread operators and their expressions
  42          * @param {ASTNode} node The node to check
  43          * @returns {void}
  44          */
  45         function checkWhiteSpace(node) {
  46             const operator = sourceCode.getFirstToken(node),
  47                 nextToken = sourceCode.getTokenAfter(operator),
  48                 hasWhitespace = sourceCode.isSpaceBetweenTokens(operator, nextToken);
  49             let type;
  50
  51             switch (node.type) {
  52                 case "SpreadElement":
  53                     type = "spread";
  54                     if (node.parent.type === "ObjectExpression") {
  55                         type += " property";
  56                     }
  57                     break;
  58                 case "RestElement":
  59                     type = "rest";
  60                     if (node.parent.type === "ObjectPattern") {
  61                         type += " property";
  62                     }
  63                     break;
  64                 case "ExperimentalSpreadProperty":
  65                     type = "spread property";
  66                     break;
  67                 case "ExperimentalRestProperty":
  68                     type = "rest property";
  69                     break;
  70                 default:
  71                     return;
  72             }
  73
  74             if (alwaysSpace && !hasWhitespace) {
  75                 context.report({
  76                     node,
  77                     loc: {
  78                         line: operator.loc.end.line,
  79                         column: operator.loc.end.column
  80                     },
  81                     message: "Expected whitespace after {{type}} operator.",
  82                     data: {
  83                         type
  84                     },
  85                     fix(fixer) {
  86                         return fixer.replaceTextRange([operator.range[1], nextToken.range[0]], " ");
  87                     }
  88                 });
  89             } else if (!alwaysSpace && hasWhitespace) {
  90                 context.report({
  91                     node,
  92                     loc: {
  93                         line: operator.loc.end.line,
  94                         column: operator.loc.end.column
  95                     },
  96                     message: "Unexpected whitespace after {{type}} operator.",
  97                     data: {
  98                         type
  99                     },
 100                     fix(fixer) {
 101                         return fixer.removeRange([operator.range[1], nextToken.range[0]]);
 102                     }
 103                 });
 104             }
 105         }
 106
 107         //--------------------------------------------------------------------------
 108         // Public
 109         //--------------------------------------------------------------------------
 110
 111         return {
 112             SpreadElement: checkWhiteSpace,
 113             RestElement: checkWhiteSpace,
 114             ExperimentalSpreadProperty: checkWhiteSpace,
 115             ExperimentalRestProperty: checkWhiteSpace
 116         };
 117     }
 118 };