1 | /**
|
2 | * @fileoverview Rule to disallow if as the only statement in an else block
|
3 | * @author Brandon Mills
|
4 | */
|
5 | ;
|
6 |
|
7 | //------------------------------------------------------------------------------
|
8 | // Rule Definition
|
9 | //------------------------------------------------------------------------------
|
10 |
|
11 | module.exports = {
|
12 | meta: {
|
13 | type: "suggestion",
|
14 |
|
15 | docs: {
|
16 | description: "disallow `if` statements as the only statement in `else` blocks",
|
17 | category: "Stylistic Issues",
|
18 | recommended: false,
|
19 | url: "https://eslint.org/docs/rules/no-lonely-if"
|
20 | },
|
21 |
|
22 | schema: [],
|
23 | fixable: "code",
|
24 |
|
25 | messages: {
|
26 | unexpectedLonelyIf: "Unexpected if as the only statement in an else block."
|
27 | }
|
28 | },
|
29 |
|
30 | create(context) {
|
31 | const sourceCode = context.getSourceCode();
|
32 |
|
33 | return {
|
34 | IfStatement(node) {
|
35 | const ancestors = context.getAncestors(),
|
36 | parent = ancestors.pop(),
|
37 | grandparent = ancestors.pop();
|
38 |
|
39 | if (parent && parent.type === "BlockStatement" &&
|
40 | parent.body.length === 1 && grandparent &&
|
41 | grandparent.type === "IfStatement" &&
|
42 | parent === grandparent.alternate) {
|
43 | context.report({
|
44 | node,
|
45 | messageId: "unexpectedLonelyIf",
|
46 | fix(fixer) {
|
47 | const openingElseCurly = sourceCode.getFirstToken(parent);
|
48 | const closingElseCurly = sourceCode.getLastToken(parent);
|
49 | const elseKeyword = sourceCode.getTokenBefore(openingElseCurly);
|
50 | const tokenAfterElseBlock = sourceCode.getTokenAfter(closingElseCurly);
|
51 | const lastIfToken = sourceCode.getLastToken(node.consequent);
|
52 | const sourceText = sourceCode.getText();
|
53 |
|
54 | if (sourceText.slice(openingElseCurly.range[1],
|
55 | node.range[0]).trim() || sourceText.slice(node.range[1], closingElseCurly.range[0]).trim()) {
|
56 |
|
57 | // Don't fix if there are any non-whitespace characters interfering (e.g. comments)
|
58 | return null;
|
59 | }
|
60 |
|
61 | if (
|
62 | node.consequent.type !== "BlockStatement" && lastIfToken.value !== ";" && tokenAfterElseBlock &&
|
63 | (
|
64 | node.consequent.loc.end.line === tokenAfterElseBlock.loc.start.line ||
|
65 | /^[([/+`-]/u.test(tokenAfterElseBlock.value) ||
|
66 | lastIfToken.value === "++" ||
|
67 | lastIfToken.value === "--"
|
68 | )
|
69 | ) {
|
70 |
|
71 | /*
|
72 | * If the `if` statement has no block, and is not followed by a semicolon, make sure that fixing
|
73 | * the issue would not change semantics due to ASI. If this would happen, don't do a fix.
|
74 | */
|
75 | return null;
|
76 | }
|
77 |
|
78 | return fixer.replaceTextRange(
|
79 | [openingElseCurly.range[0], closingElseCurly.range[1]],
|
80 | (elseKeyword.range[1] === openingElseCurly.range[0] ? " " : "") + sourceCode.getText(node)
|
81 | );
|
82 | }
|
83 | });
|
84 | }
|
85 | }
|
86 | };
|
87 |
|
88 | }
|
89 | };
|