.config/coc/extensions/node_modules/coc-prettier/node_modules/eslint/lib/rules/require-yield.js

   1 /**
   2  * @fileoverview Rule to flag the generator functions that does not have yield.
   3  * @author Toru Nagashima
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Rule Definition
  10 //------------------------------------------------------------------------------
  11
  12 module.exports = {
  13     meta: {
  14         type: "suggestion",
  15
  16         docs: {
  17             description: "require generator functions to contain `yield`",
  18             category: "ECMAScript 6",
  19             recommended: true,
  20             url: "https://eslint.org/docs/rules/require-yield"
  21         },
  22
  23         schema: []
  24     },
  25
  26     create(context) {
  27         const stack = [];
  28
  29         /**
  30          * If the node is a generator function, start counting `yield` keywords.
  31          * @param {Node} node A function node to check.
  32          * @returns {void}
  33          */
  34         function beginChecking(node) {
  35             if (node.generator) {
  36                 stack.push(0);
  37             }
  38         }
  39
  40         /**
  41          * If the node is a generator function, end counting `yield` keywords, then
  42          * reports result.
  43          * @param {Node} node A function node to check.
  44          * @returns {void}
  45          */
  46         function endChecking(node) {
  47             if (!node.generator) {
  48                 return;
  49             }
  50
  51             const countYield = stack.pop();
  52
  53             if (countYield === 0 && node.body.body.length > 0) {
  54                 context.report({ node, message: "This generator function does not have 'yield'." });
  55             }
  56         }
  57
  58         return {
  59             FunctionDeclaration: beginChecking,
  60             "FunctionDeclaration:exit": endChecking,
  61             FunctionExpression: beginChecking,
  62             "FunctionExpression:exit": endChecking,
  63
  64             // Increases the count of `yield` keyword.
  65             YieldExpression() {
  66
  67                 /* istanbul ignore else */
  68                 if (stack.length > 0) {
  69                     stack[stack.length - 1] += 1;
  70                 }
  71             }
  72         };
  73     }
  74 };