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eb39fafa DC |
1 | /** |
2 | * @fileoverview Rule to flag for-in loops without if statements inside | |
3 | * @author Nicholas C. Zakas | |
4 | */ | |
5 | ||
6 | "use strict"; | |
7 | ||
8 | //------------------------------------------------------------------------------ | |
9 | // Rule Definition | |
10 | //------------------------------------------------------------------------------ | |
11 | ||
34eeec05 | 12 | /** @type {import('../shared/types').Rule} */ |
eb39fafa DC |
13 | module.exports = { |
14 | meta: { | |
15 | type: "suggestion", | |
16 | ||
17 | docs: { | |
8f9d1d4d | 18 | description: "Require `for-in` loops to include an `if` statement", |
eb39fafa DC |
19 | recommended: false, |
20 | url: "https://eslint.org/docs/rules/guard-for-in" | |
21 | }, | |
22 | ||
23 | schema: [], | |
24 | messages: { | |
25 | wrap: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype." | |
26 | } | |
27 | }, | |
28 | ||
29 | create(context) { | |
30 | ||
31 | return { | |
32 | ||
33 | ForInStatement(node) { | |
34 | const body = node.body; | |
35 | ||
36 | // empty statement | |
37 | if (body.type === "EmptyStatement") { | |
38 | return; | |
39 | } | |
40 | ||
41 | // if statement | |
42 | if (body.type === "IfStatement") { | |
43 | return; | |
44 | } | |
45 | ||
46 | // empty block | |
47 | if (body.type === "BlockStatement" && body.body.length === 0) { | |
48 | return; | |
49 | } | |
50 | ||
51 | // block with just if statement | |
52 | if (body.type === "BlockStatement" && body.body.length === 1 && body.body[0].type === "IfStatement") { | |
53 | return; | |
54 | } | |
55 | ||
56 | // block that starts with if statement | |
57 | if (body.type === "BlockStatement" && body.body.length >= 1 && body.body[0].type === "IfStatement") { | |
58 | const i = body.body[0]; | |
59 | ||
60 | // ... whose consequent is a continue | |
61 | if (i.consequent.type === "ContinueStatement") { | |
62 | return; | |
63 | } | |
64 | ||
65 | // ... whose consequent is a block that contains only a continue | |
66 | if (i.consequent.type === "BlockStatement" && i.consequent.body.length === 1 && i.consequent.body[0].type === "ContinueStatement") { | |
67 | return; | |
68 | } | |
69 | } | |
70 | ||
71 | context.report({ node, messageId: "wrap" }); | |
72 | } | |
73 | }; | |
74 | ||
75 | } | |
76 | }; |