.config/coc/extensions/node_modules/coc-prettier/node_modules/eslint/lib/rules/no-return-assign.js

   1 /**
   2  * @fileoverview Rule to flag when return statement contains assignment
   3  * @author Ilya Volodin
   4  */
   5 "use strict";
   6
   7 //------------------------------------------------------------------------------
   8 // Requirements
   9 //------------------------------------------------------------------------------
  10
  11 const astUtils = require("./utils/ast-utils");
  12
  13 //------------------------------------------------------------------------------
  14 // Helpers
  15 //------------------------------------------------------------------------------
  16
  17 const SENTINEL_TYPE = /^(?:[a-zA-Z]+?Statement|ArrowFunctionExpression|FunctionExpression|ClassExpression)$/u;
  18
  19 //------------------------------------------------------------------------------
  20 // Rule Definition
  21 //------------------------------------------------------------------------------
  22
  23 module.exports = {
  24     meta: {
  25         type: "suggestion",
  26
  27         docs: {
  28             description: "disallow assignment operators in `return` statements",
  29             category: "Best Practices",
  30             recommended: false,
  31             url: "https://eslint.org/docs/rules/no-return-assign"
  32         },
  33
  34         schema: [
  35             {
  36                 enum: ["except-parens", "always"]
  37             }
  38         ],
  39
  40         messages: {
  41             returnAssignment: "Return statement should not contain assignment.",
  42             arrowAssignment: "Arrow function should not return assignment."
  43         }
  44     },
  45
  46     create(context) {
  47         const always = (context.options[0] || "except-parens") !== "except-parens";
  48         const sourceCode = context.getSourceCode();
  49
  50         return {
  51             AssignmentExpression(node) {
  52                 if (!always && astUtils.isParenthesised(sourceCode, node)) {
  53                     return;
  54                 }
  55
  56                 let currentChild = node;
  57                 let parent = currentChild.parent;
  58
  59                 // Find ReturnStatement or ArrowFunctionExpression in ancestors.
  60                 while (parent && !SENTINEL_TYPE.test(parent.type)) {
  61                     currentChild = parent;
  62                     parent = parent.parent;
  63                 }
  64
  65                 // Reports.
  66                 if (parent && parent.type === "ReturnStatement") {
  67                     context.report({
  68                         node: parent,
  69                         messageId: "returnAssignment"
  70                     });
  71                 } else if (parent && parent.type === "ArrowFunctionExpression" && parent.body === currentChild) {
  72                     context.report({
  73                         node: parent,
  74                         messageId: "arrowAssignment"
  75                     });
  76                 }
  77             }
  78         };
  79     }
  80 };