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