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eb39fafa DC |
1 | /** |
2 | * @fileoverview Disallows multiple blank lines. | |
3 | * implementation adapted from the no-trailing-spaces rule. | |
4 | * @author Greg Cochard | |
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: "layout", | |
16 | ||
17 | docs: { | |
8f9d1d4d | 18 | description: "Disallow multiple empty lines", |
eb39fafa | 19 | recommended: false, |
f2a92ac6 | 20 | url: "https://eslint.org/docs/latest/rules/no-multiple-empty-lines" |
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21 | }, |
22 | ||
23 | fixable: "whitespace", | |
24 | ||
25 | schema: [ | |
26 | { | |
27 | type: "object", | |
28 | properties: { | |
29 | max: { | |
30 | type: "integer", | |
31 | minimum: 0 | |
32 | }, | |
33 | maxEOF: { | |
34 | type: "integer", | |
35 | minimum: 0 | |
36 | }, | |
37 | maxBOF: { | |
38 | type: "integer", | |
39 | minimum: 0 | |
40 | } | |
41 | }, | |
42 | required: ["max"], | |
43 | additionalProperties: false | |
44 | } | |
45 | ], | |
46 | ||
47 | messages: { | |
48 | blankBeginningOfFile: "Too many blank lines at the beginning of file. Max of {{max}} allowed.", | |
49 | blankEndOfFile: "Too many blank lines at the end of file. Max of {{max}} allowed.", | |
50 | consecutiveBlank: "More than {{max}} blank {{pluralizedLines}} not allowed." | |
51 | } | |
52 | }, | |
53 | ||
54 | create(context) { | |
55 | ||
56 | // Use options.max or 2 as default | |
57 | let max = 2, | |
58 | maxEOF = max, | |
59 | maxBOF = max; | |
60 | ||
61 | if (context.options.length) { | |
62 | max = context.options[0].max; | |
63 | maxEOF = typeof context.options[0].maxEOF !== "undefined" ? context.options[0].maxEOF : max; | |
64 | maxBOF = typeof context.options[0].maxBOF !== "undefined" ? context.options[0].maxBOF : max; | |
65 | } | |
66 | ||
f2a92ac6 | 67 | const sourceCode = context.sourceCode; |
eb39fafa DC |
68 | |
69 | // Swallow the final newline, as some editors add it automatically and we don't want it to cause an issue | |
70 | const allLines = sourceCode.lines[sourceCode.lines.length - 1] === "" ? sourceCode.lines.slice(0, -1) : sourceCode.lines; | |
71 | const templateLiteralLines = new Set(); | |
72 | ||
73 | //-------------------------------------------------------------------------- | |
74 | // Public | |
75 | //-------------------------------------------------------------------------- | |
76 | ||
77 | return { | |
78 | TemplateLiteral(node) { | |
79 | node.quasis.forEach(literalPart => { | |
80 | ||
81 | // Empty lines have a semantic meaning if they're inside template literals. Don't count these as empty lines. | |
82 | for (let ignoredLine = literalPart.loc.start.line; ignoredLine < literalPart.loc.end.line; ignoredLine++) { | |
83 | templateLiteralLines.add(ignoredLine); | |
84 | } | |
85 | }); | |
86 | }, | |
87 | "Program:exit"(node) { | |
88 | return allLines | |
89 | ||
90 | // Given a list of lines, first get a list of line numbers that are non-empty. | |
91 | .reduce((nonEmptyLineNumbers, line, index) => { | |
92 | if (line.trim() || templateLiteralLines.has(index + 1)) { | |
93 | nonEmptyLineNumbers.push(index + 1); | |
94 | } | |
95 | return nonEmptyLineNumbers; | |
96 | }, []) | |
97 | ||
98 | // Add a value at the end to allow trailing empty lines to be checked. | |
99 | .concat(allLines.length + 1) | |
100 | ||
101 | // Given two line numbers of non-empty lines, report the lines between if the difference is too large. | |
102 | .reduce((lastLineNumber, lineNumber) => { | |
103 | let messageId, maxAllowed; | |
104 | ||
105 | if (lastLineNumber === 0) { | |
106 | messageId = "blankBeginningOfFile"; | |
107 | maxAllowed = maxBOF; | |
108 | } else if (lineNumber === allLines.length + 1) { | |
109 | messageId = "blankEndOfFile"; | |
110 | maxAllowed = maxEOF; | |
111 | } else { | |
112 | messageId = "consecutiveBlank"; | |
113 | maxAllowed = max; | |
114 | } | |
115 | ||
116 | if (lineNumber - lastLineNumber - 1 > maxAllowed) { | |
117 | context.report({ | |
118 | node, | |
119 | loc: { | |
120 | start: { line: lastLineNumber + maxAllowed + 1, column: 0 }, | |
121 | end: { line: lineNumber, column: 0 } | |
122 | }, | |
123 | messageId, | |
124 | data: { | |
125 | max: maxAllowed, | |
126 | pluralizedLines: maxAllowed === 1 ? "line" : "lines" | |
127 | }, | |
128 | fix(fixer) { | |
129 | const rangeStart = sourceCode.getIndexFromLoc({ line: lastLineNumber + 1, column: 0 }); | |
130 | ||
131 | /* | |
132 | * The end of the removal range is usually the start index of the next line. | |
133 | * However, at the end of the file there is no next line, so the end of the | |
134 | * range is just the length of the text. | |
135 | */ | |
136 | const lineNumberAfterRemovedLines = lineNumber - maxAllowed; | |
137 | const rangeEnd = lineNumberAfterRemovedLines <= allLines.length | |
138 | ? sourceCode.getIndexFromLoc({ line: lineNumberAfterRemovedLines, column: 0 }) | |
139 | : sourceCode.text.length; | |
140 | ||
141 | return fixer.removeRange([rangeStart, rangeEnd]); | |
142 | } | |
143 | }); | |
144 | } | |
145 | ||
146 | return lineNumber; | |
147 | }, 0); | |
148 | } | |
149 | }; | |
150 | } | |
151 | }; |