| /** |
| * @fileoverview Rule to flag for-in loops without if statements inside |
| * @author Nicholas C. Zakas |
| */ |
| |
| "use strict"; |
| |
| //------------------------------------------------------------------------------ |
| // Rule Definition |
| //------------------------------------------------------------------------------ |
| |
| module.exports = { |
| meta: { |
| type: "suggestion", |
| |
| docs: { |
| description: "require `for-in` loops to include an `if` statement", |
| category: "Best Practices", |
| recommended: false, |
| url: "https://eslint.org/docs/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" }); |
| } |
| }; |
| |
| } |
| }; |