| /** | |
|  * @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 { upperCaseFirst } = require("../shared/string-utils"); | |
| 
 | |
| //------------------------------------------------------------------------------ | |
| // 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(); | |
| 
 | |
|     comments.forEach(comment => { | |
|         for (let i = comment.loc.start.line; i <= comment.loc.end.line; i++) { | |
|             map.set(i, comment); | |
|         } | |
|     }); | |
|     return map; | |
| } | |
| 
 | |
| //------------------------------------------------------------------------------ | |
| // Rule Definition | |
| //------------------------------------------------------------------------------ | |
|  | |
| /** @type {import('../shared/types').Rule} */ | |
| module.exports = { | |
|     meta: { | |
|         type: "suggestion", | |
| 
 | |
|         docs: { | |
|             description: "Enforce a maximum number of lines of code in a function", | |
|             recommended: false, | |
|             url: "https://eslint.org/docs/latest/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.sourceCode; | |
|         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.type === "ArrowFunctionExpression") && 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 = upperCaseFirst(astUtils.getFunctionNameWithKind(funcNode)); | |
| 
 | |
|                 context.report({ | |
|                     node, | |
|                     messageId: "exceed", | |
|                     data: { name, lineCount, maxLines } | |
|                 }); | |
|             } | |
|         } | |
| 
 | |
|         //-------------------------------------------------------------------------- | |
|         // Public API | |
|         //-------------------------------------------------------------------------- | |
|  | |
|         return { | |
|             FunctionDeclaration: processFunction, | |
|             FunctionExpression: processFunction, | |
|             ArrowFunctionExpression: processFunction | |
|         }; | |
|     } | |
| };
 |