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| /** | |
| * @fileoverview A rule to set the maximum number of line of code in a function. | |
| * @author Pete Ward <peteward44@gmail.com> | |
| */ | |
| "use strict"; | |
| //------------------------------------------------------------------------------ | |
| // Requirements | |
| //------------------------------------------------------------------------------ | |
| const astUtils = require("./utils/ast-utils"); | |
| const lodash = require("lodash"); | |
| //------------------------------------------------------------------------------ | |
| // Constants | |
| //------------------------------------------------------------------------------ | |
| const OPTIONS_SCHEMA = { | |
| type: "object", | |
| properties: { | |
| max: { | |
| type: "integer", | |
| minimum: 0 | |
| }, | |
| skipComments: { | |
| type: "boolean" | |
| }, | |
| skipBlankLines: { | |
| type: "boolean" | |
| }, | |
| IIFEs: { | |
| type: "boolean" | |
| } | |
| }, | |
| additionalProperties: false | |
| }; | |
| const OPTIONS_OR_INTEGER_SCHEMA = { | |
| oneOf: [ | |
| OPTIONS_SCHEMA, | |
| { | |
| type: "integer", | |
| minimum: 1 | |
| } | |
| ] | |
| }; | |
| /** | |
| * Given a list of comment nodes, return a map with numeric keys (source code line numbers) and comment token values. | |
| * @param {Array} comments An array of comment nodes. | |
| * @returns {Map.<string,Node>} A map with numeric keys (source code line numbers) and comment token values. | |
| */ | |
| function getCommentLineNumbers(comments) { | |
| const map = new Map(); | |
| if (!comments) { | |
| return map; | |
| } | |
| comments.forEach(comment => { | |
| for (let i = comment.loc.start.line; i <= comment.loc.end.line; i++) { | |
| map.set(i, comment); | |
| } | |
| }); | |
| return map; | |
| } | |
| //------------------------------------------------------------------------------ | |
| // Rule Definition | |
| //------------------------------------------------------------------------------ | |
| module.exports = { | |
| meta: { | |
| type: "suggestion", | |
| docs: { | |
| description: "enforce a maximum number of line of code in a function", | |
| category: "Stylistic Issues", | |
| recommended: false, | |
| url: "https://eslint.org/docs/rules/max-lines-per-function" | |
| }, | |
| schema: [ | |
| OPTIONS_OR_INTEGER_SCHEMA | |
| ], | |
| messages: { | |
| exceed: "{{name}} has too many lines ({{lineCount}}). Maximum allowed is {{maxLines}}." | |
| } | |
| }, | |
| create(context) { | |
| const sourceCode = context.getSourceCode(); | |
| const lines = sourceCode.lines; | |
| const option = context.options[0]; | |
| let maxLines = 50; | |
| let skipComments = false; | |
| let skipBlankLines = false; | |
| let IIFEs = false; | |
| if (typeof option === "object") { | |
| maxLines = typeof option.max === "number" ? option.max : 50; | |
| skipComments = !!option.skipComments; | |
| skipBlankLines = !!option.skipBlankLines; | |
| IIFEs = !!option.IIFEs; | |
| } else if (typeof option === "number") { | |
| maxLines = option; | |
| } | |
| const commentLineNumbers = getCommentLineNumbers(sourceCode.getAllComments()); | |
| //-------------------------------------------------------------------------- | |
| // Helpers | |
| //-------------------------------------------------------------------------- | |
| /** | |
| * Tells if a comment encompasses the entire line. | |
| * @param {string} line The source line with a trailing comment | |
| * @param {number} lineNumber The one-indexed line number this is on | |
| * @param {ASTNode} comment The comment to remove | |
| * @returns {boolean} If the comment covers the entire line | |
| */ | |
| function isFullLineComment(line, lineNumber, comment) { | |
| const start = comment.loc.start, | |
| end = comment.loc.end, | |
| isFirstTokenOnLine = start.line === lineNumber && !line.slice(0, start.column).trim(), | |
| isLastTokenOnLine = end.line === lineNumber && !line.slice(end.column).trim(); | |
| return comment && | |
| (start.line < lineNumber || isFirstTokenOnLine) && | |
| (end.line > lineNumber || isLastTokenOnLine); | |
| } | |
| /** | |
| * Identifies is a node is a FunctionExpression which is part of an IIFE | |
| * @param {ASTNode} node Node to test | |
| * @returns {boolean} True if it's an IIFE | |
| */ | |
| function isIIFE(node) { | |
| return node.type === "FunctionExpression" && node.parent && node.parent.type === "CallExpression" && node.parent.callee === node; | |
| } | |
| /** | |
| * Identifies is a node is a FunctionExpression which is embedded within a MethodDefinition or Property | |
| * @param {ASTNode} node Node to test | |
| * @returns {boolean} True if it's a FunctionExpression embedded within a MethodDefinition or Property | |
| */ | |
| function isEmbedded(node) { | |
| if (!node.parent) { | |
| return false; | |
| } | |
| if (node !== node.parent.value) { | |
| return false; | |
| } | |
| if (node.parent.type === "MethodDefinition") { | |
| return true; | |
| } | |
| if (node.parent.type === "Property") { | |
| return node.parent.method === true || node.parent.kind === "get" || node.parent.kind === "set"; | |
| } | |
| return false; | |
| } | |
| /** | |
| * Count the lines in the function | |
| * @param {ASTNode} funcNode Function AST node | |
| * @returns {void} | |
| * @private | |
| */ | |
| function processFunction(funcNode) { | |
| const node = isEmbedded(funcNode) ? funcNode.parent : funcNode; | |
| if (!IIFEs && isIIFE(node)) { | |
| return; | |
| } | |
| let lineCount = 0; | |
| for (let i = node.loc.start.line - 1; i < node.loc.end.line; ++i) { | |
| const line = lines[i]; | |
| if (skipComments) { | |
| if (commentLineNumbers.has(i + 1) && isFullLineComment(line, i + 1, commentLineNumbers.get(i + 1))) { | |
| continue; | |
| } | |
| } | |
| if (skipBlankLines) { | |
| if (line.match(/^\s*$/u)) { | |
| continue; | |
| } | |
| } | |
| lineCount++; | |
| } | |
| if (lineCount > maxLines) { | |
| const name = lodash.upperFirst(astUtils.getFunctionNameWithKind(funcNode)); | |
| context.report({ | |
| node, | |
| messageId: "exceed", | |
| data: { name, lineCount, maxLines } | |
| }); | |
| } | |
| } | |
| //-------------------------------------------------------------------------- | |
| // Public API | |
| //-------------------------------------------------------------------------- | |
| return { | |
| FunctionDeclaration: processFunction, | |
| FunctionExpression: processFunction, | |
| ArrowFunctionExpression: processFunction | |
| }; | |
| } | |
| }; |