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| /** | |
| * @fileoverview Disallows multiple blank lines. | |
| * implementation adapted from the no-trailing-spaces rule. | |
| * @author Greg Cochard | |
| */ | |
| "use strict"; | |
| //------------------------------------------------------------------------------ | |
| // Rule Definition | |
| //------------------------------------------------------------------------------ | |
| module.exports = { | |
| meta: { | |
| type: "layout", | |
| docs: { | |
| description: "disallow multiple empty lines", | |
| category: "Stylistic Issues", | |
| recommended: false, | |
| url: "https://eslint.org/docs/rules/no-multiple-empty-lines" | |
| }, | |
| fixable: "whitespace", | |
| schema: [ | |
| { | |
| type: "object", | |
| properties: { | |
| max: { | |
| type: "integer", | |
| minimum: 0 | |
| }, | |
| maxEOF: { | |
| type: "integer", | |
| minimum: 0 | |
| }, | |
| maxBOF: { | |
| type: "integer", | |
| minimum: 0 | |
| } | |
| }, | |
| required: ["max"], | |
| additionalProperties: false | |
| } | |
| ] | |
| }, | |
| create(context) { | |
| // Use options.max or 2 as default | |
| let max = 2, | |
| maxEOF = max, | |
| maxBOF = max; | |
| if (context.options.length) { | |
| max = context.options[0].max; | |
| maxEOF = typeof context.options[0].maxEOF !== "undefined" ? context.options[0].maxEOF : max; | |
| maxBOF = typeof context.options[0].maxBOF !== "undefined" ? context.options[0].maxBOF : max; | |
| } | |
| const sourceCode = context.getSourceCode(); | |
| // Swallow the final newline, as some editors add it automatically and we don't want it to cause an issue | |
| const allLines = sourceCode.lines[sourceCode.lines.length - 1] === "" ? sourceCode.lines.slice(0, -1) : sourceCode.lines; | |
| const templateLiteralLines = new Set(); | |
| //-------------------------------------------------------------------------- | |
| // Public | |
| //-------------------------------------------------------------------------- | |
| return { | |
| TemplateLiteral(node) { | |
| node.quasis.forEach(literalPart => { | |
| // Empty lines have a semantic meaning if they're inside template literals. Don't count these as empty lines. | |
| for (let ignoredLine = literalPart.loc.start.line; ignoredLine < literalPart.loc.end.line; ignoredLine++) { | |
| templateLiteralLines.add(ignoredLine); | |
| } | |
| }); | |
| }, | |
| "Program:exit"(node) { | |
| return allLines | |
| // Given a list of lines, first get a list of line numbers that are non-empty. | |
| .reduce((nonEmptyLineNumbers, line, index) => { | |
| if (line.trim() || templateLiteralLines.has(index + 1)) { | |
| nonEmptyLineNumbers.push(index + 1); | |
| } | |
| return nonEmptyLineNumbers; | |
| }, []) | |
| // Add a value at the end to allow trailing empty lines to be checked. | |
| .concat(allLines.length + 1) | |
| // Given two line numbers of non-empty lines, report the lines between if the difference is too large. | |
| .reduce((lastLineNumber, lineNumber) => { | |
| let message, maxAllowed; | |
| if (lastLineNumber === 0) { | |
| message = "Too many blank lines at the beginning of file. Max of {{max}} allowed."; | |
| maxAllowed = maxBOF; | |
| } else if (lineNumber === allLines.length + 1) { | |
| message = "Too many blank lines at the end of file. Max of {{max}} allowed."; | |
| maxAllowed = maxEOF; | |
| } else { | |
| message = "More than {{max}} blank {{pluralizedLines}} not allowed."; | |
| maxAllowed = max; | |
| } | |
| if (lineNumber - lastLineNumber - 1 > maxAllowed) { | |
| context.report({ | |
| node, | |
| loc: { start: { line: lastLineNumber + 1, column: 0 }, end: { line: lineNumber, column: 0 } }, | |
| message, | |
| data: { max: maxAllowed, pluralizedLines: maxAllowed === 1 ? "line" : "lines" }, | |
| fix(fixer) { | |
| const rangeStart = sourceCode.getIndexFromLoc({ line: lastLineNumber + 1, column: 0 }); | |
| /* | |
| * The end of the removal range is usually the start index of the next line. | |
| * However, at the end of the file there is no next line, so the end of the | |
| * range is just the length of the text. | |
| */ | |
| const lineNumberAfterRemovedLines = lineNumber - maxAllowed; | |
| const rangeEnd = lineNumberAfterRemovedLines <= allLines.length | |
| ? sourceCode.getIndexFromLoc({ line: lineNumberAfterRemovedLines, column: 0 }) | |
| : sourceCode.text.length; | |
| return fixer.removeRange([rangeStart, rangeEnd]); | |
| } | |
| }); | |
| } | |
| return lineNumber; | |
| }, 0); | |
| } | |
| }; | |
| } | |
| }; |