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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 | ||
12 | module.exports = { | |
13 | meta: { | |
14 | type: "suggestion", | |
15 | ||
16 | docs: { | |
17 | description: "require `for-in` loops to include an `if` statement", | |
eb39fafa DC |
18 | recommended: false, |
19 | url: "https://eslint.org/docs/rules/guard-for-in" | |
20 | }, | |
21 | ||
22 | schema: [], | |
23 | messages: { | |
24 | wrap: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype." | |
25 | } | |
26 | }, | |
27 | ||
28 | create(context) { | |
29 | ||
30 | return { | |
31 | ||
32 | ForInStatement(node) { | |
33 | const body = node.body; | |
34 | ||
35 | // empty statement | |
36 | if (body.type === "EmptyStatement") { | |
37 | return; | |
38 | } | |
39 | ||
40 | // if statement | |
41 | if (body.type === "IfStatement") { | |
42 | return; | |
43 | } | |
44 | ||
45 | // empty block | |
46 | if (body.type === "BlockStatement" && body.body.length === 0) { | |
47 | return; | |
48 | } | |
49 | ||
50 | // block with just if statement | |
51 | if (body.type === "BlockStatement" && body.body.length === 1 && body.body[0].type === "IfStatement") { | |
52 | return; | |
53 | } | |
54 | ||
55 | // block that starts with if statement | |
56 | if (body.type === "BlockStatement" && body.body.length >= 1 && body.body[0].type === "IfStatement") { | |
57 | const i = body.body[0]; | |
58 | ||
59 | // ... whose consequent is a continue | |
60 | if (i.consequent.type === "ContinueStatement") { | |
61 | return; | |
62 | } | |
63 | ||
64 | // ... whose consequent is a block that contains only a continue | |
65 | if (i.consequent.type === "BlockStatement" && i.consequent.body.length === 1 && i.consequent.body[0].type === "ContinueStatement") { | |
66 | return; | |
67 | } | |
68 | } | |
69 | ||
70 | context.report({ node, messageId: "wrap" }); | |
71 | } | |
72 | }; | |
73 | ||
74 | } | |
75 | }; |