no-sparse-arrays.js

   1 /**
   2  * @fileoverview Disallow sparse arrays
   3  * @author Nicholas C. Zakas
   4  */
   5 "use strict";
   6
   7 //------------------------------------------------------------------------------
   8 // Rule Definition
   9 //------------------------------------------------------------------------------
  10
  11 module.exports = {
  12     meta: {
  13         type: "problem",
  14
  15         docs: {
  16             description: "disallow sparse arrays",
  17             category: "Possible Errors",
  18             recommended: true,
  19             url: "https://eslint.org/docs/rules/no-sparse-arrays"
  20         },
  21
  22         schema: []
  23     },
  24
  25     create(context) {
  26
  27
  28         //--------------------------------------------------------------------------
  29         // Public
  30         //--------------------------------------------------------------------------
  31
  32         return {
  33
  34             ArrayExpression(node) {
  35
  36                 const emptySpot = node.elements.indexOf(null) > -1;
  37
  38                 if (emptySpot) {
  39                     context.report({ node, message: "Unexpected comma in middle of array." });
  40                 }
  41             }
  42
  43         };
  44
  45     }
  46 };