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