| /** | |
|  * @fileoverview Rule to flag for-in loops without if statements inside | |
|  * @author Nicholas C. Zakas | |
|  */ | |
| 
 | |
| "use strict"; | |
| 
 | |
| //------------------------------------------------------------------------------ | |
| // Rule Definition | |
| //------------------------------------------------------------------------------ | |
|  | |
| /** @type {import('../shared/types').Rule} */ | |
| module.exports = { | |
|     meta: { | |
|         type: "suggestion", | |
| 
 | |
|         docs: { | |
|             description: "Require `for-in` loops to include an `if` statement", | |
|             recommended: false, | |
|             url: "https://eslint.org/docs/latest/rules/guard-for-in" | |
|         }, | |
| 
 | |
|         schema: [], | |
|         messages: { | |
|             wrap: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype." | |
|         } | |
|     }, | |
| 
 | |
|     create(context) { | |
| 
 | |
|         return { | |
| 
 | |
|             ForInStatement(node) { | |
|                 const body = node.body; | |
| 
 | |
|                 // empty statement | |
|                 if (body.type === "EmptyStatement") { | |
|                     return; | |
|                 } | |
| 
 | |
|                 // if statement | |
|                 if (body.type === "IfStatement") { | |
|                     return; | |
|                 } | |
| 
 | |
|                 // empty block | |
|                 if (body.type === "BlockStatement" && body.body.length === 0) { | |
|                     return; | |
|                 } | |
| 
 | |
|                 // block with just if statement | |
|                 if (body.type === "BlockStatement" && body.body.length === 1 && body.body[0].type === "IfStatement") { | |
|                     return; | |
|                 } | |
| 
 | |
|                 // block that starts with if statement | |
|                 if (body.type === "BlockStatement" && body.body.length >= 1 && body.body[0].type === "IfStatement") { | |
|                     const i = body.body[0]; | |
| 
 | |
|                     // ... whose consequent is a continue | |
|                     if (i.consequent.type === "ContinueStatement") { | |
|                         return; | |
|                     } | |
| 
 | |
|                     // ... whose consequent is a block that contains only a continue | |
|                     if (i.consequent.type === "BlockStatement" && i.consequent.body.length === 1 && i.consequent.body[0].type === "ContinueStatement") { | |
|                         return; | |
|                     } | |
|                 } | |
| 
 | |
|                 context.report({ node, messageId: "wrap" }); | |
|             } | |
|         }; | |
| 
 | |
|     } | |
| };
 |