374 lines
13 KiB
JavaScript
374 lines
13 KiB
JavaScript
/**
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* @fileoverview Rule to check for max length on a line.
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* @author Matt DuVall <http://www.mattduvall.com>
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Constants
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//------------------------------------------------------------------------------
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const OPTIONS_SCHEMA = {
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type: "object",
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properties: {
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code: {
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type: "integer",
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minimum: 0
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},
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comments: {
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type: "integer",
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minimum: 0
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},
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tabWidth: {
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type: "integer",
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minimum: 0
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},
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ignorePattern: {
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type: "string"
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},
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ignoreComments: {
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type: "boolean"
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},
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ignoreStrings: {
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type: "boolean"
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},
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ignoreUrls: {
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type: "boolean"
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},
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ignoreTemplateLiterals: {
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type: "boolean"
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},
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ignoreRegExpLiterals: {
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type: "boolean"
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},
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ignoreTrailingComments: {
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type: "boolean"
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}
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},
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additionalProperties: false
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};
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const OPTIONS_OR_INTEGER_SCHEMA = {
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anyOf: [
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OPTIONS_SCHEMA,
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{
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type: "integer",
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minimum: 0
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}
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]
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};
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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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docs: {
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description: "enforce a maximum line length",
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category: "Stylistic Issues",
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recommended: false,
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url: "https://eslint.org/docs/rules/max-len"
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},
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schema: [
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OPTIONS_OR_INTEGER_SCHEMA,
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OPTIONS_OR_INTEGER_SCHEMA,
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OPTIONS_SCHEMA
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]
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},
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create(context) {
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/*
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* Inspired by http://tools.ietf.org/html/rfc3986#appendix-B, however:
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* - They're matching an entire string that we know is a URI
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* - We're matching part of a string where we think there *might* be a URL
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* - We're only concerned about URLs, as picking out any URI would cause
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* too many false positives
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* - We don't care about matching the entire URL, any small segment is fine
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*/
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const URL_REGEXP = /[^:/?#]:\/\/[^?#]/;
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const sourceCode = context.getSourceCode();
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/**
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* Computes the length of a line that may contain tabs. The width of each
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* tab will be the number of spaces to the next tab stop.
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* @param {string} line The line.
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* @param {int} tabWidth The width of each tab stop in spaces.
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* @returns {int} The computed line length.
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* @private
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*/
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function computeLineLength(line, tabWidth) {
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let extraCharacterCount = 0;
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line.replace(/\t/g, (match, offset) => {
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const totalOffset = offset + extraCharacterCount,
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previousTabStopOffset = tabWidth ? totalOffset % tabWidth : 0,
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spaceCount = tabWidth - previousTabStopOffset;
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extraCharacterCount += spaceCount - 1; // -1 for the replaced tab
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});
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return Array.from(line).length + extraCharacterCount;
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}
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// The options object must be the last option specified…
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const lastOption = context.options[context.options.length - 1];
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const options = typeof lastOption === "object" ? Object.create(lastOption) : {};
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// …but max code length…
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if (typeof context.options[0] === "number") {
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options.code = context.options[0];
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}
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// …and tabWidth can be optionally specified directly as integers.
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if (typeof context.options[1] === "number") {
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options.tabWidth = context.options[1];
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}
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const maxLength = options.code || 80,
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tabWidth = options.tabWidth || 4,
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ignoreComments = options.ignoreComments || false,
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ignoreStrings = options.ignoreStrings || false,
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ignoreTemplateLiterals = options.ignoreTemplateLiterals || false,
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ignoreRegExpLiterals = options.ignoreRegExpLiterals || false,
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ignoreTrailingComments = options.ignoreTrailingComments || options.ignoreComments || false,
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ignoreUrls = options.ignoreUrls || false,
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maxCommentLength = options.comments;
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let ignorePattern = options.ignorePattern || null;
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if (ignorePattern) {
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ignorePattern = new RegExp(ignorePattern);
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}
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//--------------------------------------------------------------------------
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// Helpers
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//--------------------------------------------------------------------------
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/**
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* Tells if a given comment is trailing: it starts on the current line and
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* extends to or past the end of the current line.
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* @param {string} line The source line we want to check for a trailing comment on
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* @param {number} lineNumber The one-indexed line number for line
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* @param {ASTNode} comment The comment to inspect
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* @returns {boolean} If the comment is trailing on the given line
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*/
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function isTrailingComment(line, lineNumber, comment) {
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return comment &&
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(comment.loc.start.line === lineNumber && lineNumber <= comment.loc.end.line) &&
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(comment.loc.end.line > lineNumber || comment.loc.end.column === line.length);
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}
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/**
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* Tells if a comment encompasses the entire line.
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* @param {string} line The source line with a trailing comment
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* @param {number} lineNumber The one-indexed line number this is on
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* @param {ASTNode} comment The comment to remove
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* @returns {boolean} If the comment covers the entire line
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*/
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function isFullLineComment(line, lineNumber, comment) {
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const start = comment.loc.start,
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end = comment.loc.end,
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isFirstTokenOnLine = !line.slice(0, comment.loc.start.column).trim();
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return comment &&
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(start.line < lineNumber || (start.line === lineNumber && isFirstTokenOnLine)) &&
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(end.line > lineNumber || (end.line === lineNumber && end.column === line.length));
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}
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/**
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* Gets the line after the comment and any remaining trailing whitespace is
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* stripped.
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* @param {string} line The source line with a trailing comment
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* @param {ASTNode} comment The comment to remove
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* @returns {string} Line without comment and trailing whitepace
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*/
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function stripTrailingComment(line, comment) {
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// loc.column is zero-indexed
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return line.slice(0, comment.loc.start.column).replace(/\s+$/, "");
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}
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/**
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* Ensure that an array exists at [key] on `object`, and add `value` to it.
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*
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* @param {Object} object the object to mutate
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* @param {string} key the object's key
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* @param {*} value the value to add
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* @returns {void}
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* @private
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*/
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function ensureArrayAndPush(object, key, value) {
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if (!Array.isArray(object[key])) {
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object[key] = [];
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}
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object[key].push(value);
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}
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/**
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* Retrieves an array containing all strings (" or ') in the source code.
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*
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* @returns {ASTNode[]} An array of string nodes.
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*/
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function getAllStrings() {
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return sourceCode.ast.tokens.filter(token => (token.type === "String" ||
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(token.type === "JSXText" && sourceCode.getNodeByRangeIndex(token.range[0] - 1).type === "JSXAttribute")));
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}
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/**
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* Retrieves an array containing all template literals in the source code.
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*
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* @returns {ASTNode[]} An array of template literal nodes.
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*/
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function getAllTemplateLiterals() {
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return sourceCode.ast.tokens.filter(token => token.type === "Template");
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}
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/**
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* Retrieves an array containing all RegExp literals in the source code.
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*
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* @returns {ASTNode[]} An array of RegExp literal nodes.
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*/
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function getAllRegExpLiterals() {
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return sourceCode.ast.tokens.filter(token => token.type === "RegularExpression");
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}
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/**
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* A reducer to group an AST node by line number, both start and end.
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*
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* @param {Object} acc the accumulator
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* @param {ASTNode} node the AST node in question
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* @returns {Object} the modified accumulator
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* @private
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*/
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function groupByLineNumber(acc, node) {
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for (let i = node.loc.start.line; i <= node.loc.end.line; ++i) {
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ensureArrayAndPush(acc, i, node);
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}
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return acc;
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}
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/**
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* Check the program for max length
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* @param {ASTNode} node Node to examine
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* @returns {void}
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* @private
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*/
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function checkProgramForMaxLength(node) {
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// split (honors line-ending)
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const lines = sourceCode.lines,
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// list of comments to ignore
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comments = ignoreComments || maxCommentLength || ignoreTrailingComments ? sourceCode.getAllComments() : [];
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// we iterate over comments in parallel with the lines
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let commentsIndex = 0;
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const strings = getAllStrings();
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const stringsByLine = strings.reduce(groupByLineNumber, {});
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const templateLiterals = getAllTemplateLiterals();
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const templateLiteralsByLine = templateLiterals.reduce(groupByLineNumber, {});
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const regExpLiterals = getAllRegExpLiterals();
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const regExpLiteralsByLine = regExpLiterals.reduce(groupByLineNumber, {});
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lines.forEach((line, i) => {
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// i is zero-indexed, line numbers are one-indexed
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const lineNumber = i + 1;
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/*
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* if we're checking comment length; we need to know whether this
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* line is a comment
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*/
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let lineIsComment = false;
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let textToMeasure;
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/*
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* We can short-circuit the comment checks if we're already out of
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* comments to check.
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*/
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if (commentsIndex < comments.length) {
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let comment = null;
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// iterate over comments until we find one past the current line
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do {
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comment = comments[++commentsIndex];
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} while (comment && comment.loc.start.line <= lineNumber);
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// and step back by one
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comment = comments[--commentsIndex];
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if (isFullLineComment(line, lineNumber, comment)) {
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lineIsComment = true;
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textToMeasure = line;
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} else if (ignoreTrailingComments && isTrailingComment(line, lineNumber, comment)) {
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textToMeasure = stripTrailingComment(line, comment);
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} else {
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textToMeasure = line;
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}
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} else {
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textToMeasure = line;
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}
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if (ignorePattern && ignorePattern.test(textToMeasure) ||
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ignoreUrls && URL_REGEXP.test(textToMeasure) ||
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ignoreStrings && stringsByLine[lineNumber] ||
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ignoreTemplateLiterals && templateLiteralsByLine[lineNumber] ||
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ignoreRegExpLiterals && regExpLiteralsByLine[lineNumber]
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) {
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// ignore this line
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return;
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}
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const lineLength = computeLineLength(textToMeasure, tabWidth);
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const commentLengthApplies = lineIsComment && maxCommentLength;
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if (lineIsComment && ignoreComments) {
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return;
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}
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if (commentLengthApplies) {
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if (lineLength > maxCommentLength) {
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context.report({
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node,
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loc: { line: lineNumber, column: 0 },
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message: "Line {{lineNumber}} exceeds the maximum comment line length of {{maxCommentLength}}.",
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data: {
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lineNumber: i + 1,
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maxCommentLength
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}
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});
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}
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} else if (lineLength > maxLength) {
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context.report({
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node,
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loc: { line: lineNumber, column: 0 },
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message: "Line {{lineNumber}} exceeds the maximum line length of {{maxLength}}.",
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data: {
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lineNumber: i + 1,
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maxLength
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}
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});
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}
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});
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}
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//--------------------------------------------------------------------------
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// Public API
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//--------------------------------------------------------------------------
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return {
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Program: checkProgramForMaxLength
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};
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}
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};
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