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eb39fafa DC |
1 | /** |
2 | * @fileoverview A rule to set the maximum number of line of code in a function. | |
3 | * @author Pete Ward <peteward44@gmail.com> | |
4 | */ | |
5 | "use strict"; | |
6 | ||
7 | //------------------------------------------------------------------------------ | |
8 | // Requirements | |
9 | //------------------------------------------------------------------------------ | |
10 | ||
11 | const astUtils = require("./utils/ast-utils"); | |
12 | ||
13 | const lodash = require("lodash"); | |
14 | ||
15 | //------------------------------------------------------------------------------ | |
16 | // Constants | |
17 | //------------------------------------------------------------------------------ | |
18 | ||
19 | const OPTIONS_SCHEMA = { | |
20 | type: "object", | |
21 | properties: { | |
22 | max: { | |
23 | type: "integer", | |
24 | minimum: 0 | |
25 | }, | |
26 | skipComments: { | |
27 | type: "boolean" | |
28 | }, | |
29 | skipBlankLines: { | |
30 | type: "boolean" | |
31 | }, | |
32 | IIFEs: { | |
33 | type: "boolean" | |
34 | } | |
35 | }, | |
36 | additionalProperties: false | |
37 | }; | |
38 | ||
39 | const OPTIONS_OR_INTEGER_SCHEMA = { | |
40 | oneOf: [ | |
41 | OPTIONS_SCHEMA, | |
42 | { | |
43 | type: "integer", | |
44 | minimum: 1 | |
45 | } | |
46 | ] | |
47 | }; | |
48 | ||
49 | /** | |
50 | * Given a list of comment nodes, return a map with numeric keys (source code line numbers) and comment token values. | |
51 | * @param {Array} comments An array of comment nodes. | |
52 | * @returns {Map.<string,Node>} A map with numeric keys (source code line numbers) and comment token values. | |
53 | */ | |
54 | function getCommentLineNumbers(comments) { | |
55 | const map = new Map(); | |
56 | ||
57 | comments.forEach(comment => { | |
58 | for (let i = comment.loc.start.line; i <= comment.loc.end.line; i++) { | |
59 | map.set(i, comment); | |
60 | } | |
61 | }); | |
62 | return map; | |
63 | } | |
64 | ||
65 | //------------------------------------------------------------------------------ | |
66 | // Rule Definition | |
67 | //------------------------------------------------------------------------------ | |
68 | ||
69 | module.exports = { | |
70 | meta: { | |
71 | type: "suggestion", | |
72 | ||
73 | docs: { | |
74 | description: "enforce a maximum number of line of code in a function", | |
75 | category: "Stylistic Issues", | |
76 | recommended: false, | |
77 | url: "https://eslint.org/docs/rules/max-lines-per-function" | |
78 | }, | |
79 | ||
80 | schema: [ | |
81 | OPTIONS_OR_INTEGER_SCHEMA | |
82 | ], | |
83 | messages: { | |
84 | exceed: "{{name}} has too many lines ({{lineCount}}). Maximum allowed is {{maxLines}}." | |
85 | } | |
86 | }, | |
87 | ||
88 | create(context) { | |
89 | const sourceCode = context.getSourceCode(); | |
90 | const lines = sourceCode.lines; | |
91 | ||
92 | const option = context.options[0]; | |
93 | let maxLines = 50; | |
94 | let skipComments = false; | |
95 | let skipBlankLines = false; | |
96 | let IIFEs = false; | |
97 | ||
98 | if (typeof option === "object") { | |
99 | maxLines = typeof option.max === "number" ? option.max : 50; | |
100 | skipComments = !!option.skipComments; | |
101 | skipBlankLines = !!option.skipBlankLines; | |
102 | IIFEs = !!option.IIFEs; | |
103 | } else if (typeof option === "number") { | |
104 | maxLines = option; | |
105 | } | |
106 | ||
107 | const commentLineNumbers = getCommentLineNumbers(sourceCode.getAllComments()); | |
108 | ||
109 | //-------------------------------------------------------------------------- | |
110 | // Helpers | |
111 | //-------------------------------------------------------------------------- | |
112 | ||
113 | /** | |
114 | * Tells if a comment encompasses the entire line. | |
115 | * @param {string} line The source line with a trailing comment | |
116 | * @param {number} lineNumber The one-indexed line number this is on | |
117 | * @param {ASTNode} comment The comment to remove | |
118 | * @returns {boolean} If the comment covers the entire line | |
119 | */ | |
120 | function isFullLineComment(line, lineNumber, comment) { | |
121 | const start = comment.loc.start, | |
122 | end = comment.loc.end, | |
123 | isFirstTokenOnLine = start.line === lineNumber && !line.slice(0, start.column).trim(), | |
124 | isLastTokenOnLine = end.line === lineNumber && !line.slice(end.column).trim(); | |
125 | ||
126 | return comment && | |
127 | (start.line < lineNumber || isFirstTokenOnLine) && | |
128 | (end.line > lineNumber || isLastTokenOnLine); | |
129 | } | |
130 | ||
131 | /** | |
132 | * Identifies is a node is a FunctionExpression which is part of an IIFE | |
133 | * @param {ASTNode} node Node to test | |
134 | * @returns {boolean} True if it's an IIFE | |
135 | */ | |
136 | function isIIFE(node) { | |
ebb53d86 | 137 | return (node.type === "FunctionExpression" || node.type === "ArrowFunctionExpression") && node.parent && node.parent.type === "CallExpression" && node.parent.callee === node; |
eb39fafa DC |
138 | } |
139 | ||
140 | /** | |
141 | * Identifies is a node is a FunctionExpression which is embedded within a MethodDefinition or Property | |
142 | * @param {ASTNode} node Node to test | |
143 | * @returns {boolean} True if it's a FunctionExpression embedded within a MethodDefinition or Property | |
144 | */ | |
145 | function isEmbedded(node) { | |
146 | if (!node.parent) { | |
147 | return false; | |
148 | } | |
149 | if (node !== node.parent.value) { | |
150 | return false; | |
151 | } | |
152 | if (node.parent.type === "MethodDefinition") { | |
153 | return true; | |
154 | } | |
155 | if (node.parent.type === "Property") { | |
156 | return node.parent.method === true || node.parent.kind === "get" || node.parent.kind === "set"; | |
157 | } | |
158 | return false; | |
159 | } | |
160 | ||
161 | /** | |
162 | * Count the lines in the function | |
163 | * @param {ASTNode} funcNode Function AST node | |
164 | * @returns {void} | |
165 | * @private | |
166 | */ | |
167 | function processFunction(funcNode) { | |
168 | const node = isEmbedded(funcNode) ? funcNode.parent : funcNode; | |
169 | ||
170 | if (!IIFEs && isIIFE(node)) { | |
171 | return; | |
172 | } | |
173 | let lineCount = 0; | |
174 | ||
175 | for (let i = node.loc.start.line - 1; i < node.loc.end.line; ++i) { | |
176 | const line = lines[i]; | |
177 | ||
178 | if (skipComments) { | |
179 | if (commentLineNumbers.has(i + 1) && isFullLineComment(line, i + 1, commentLineNumbers.get(i + 1))) { | |
180 | continue; | |
181 | } | |
182 | } | |
183 | ||
184 | if (skipBlankLines) { | |
185 | if (line.match(/^\s*$/u)) { | |
186 | continue; | |
187 | } | |
188 | } | |
189 | ||
190 | lineCount++; | |
191 | } | |
192 | ||
193 | if (lineCount > maxLines) { | |
194 | const name = lodash.upperFirst(astUtils.getFunctionNameWithKind(funcNode)); | |
195 | ||
196 | context.report({ | |
197 | node, | |
198 | messageId: "exceed", | |
199 | data: { name, lineCount, maxLines } | |
200 | }); | |
201 | } | |
202 | } | |
203 | ||
204 | //-------------------------------------------------------------------------- | |
205 | // Public API | |
206 | //-------------------------------------------------------------------------- | |
207 | ||
208 | return { | |
209 | FunctionDeclaration: processFunction, | |
210 | FunctionExpression: processFunction, | |
211 | ArrowFunctionExpression: processFunction | |
212 | }; | |
213 | } | |
214 | }; |