196 lines
7.3 KiB
JavaScript
196 lines
7.3 KiB
JavaScript
/**
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* @fileoverview Specify the maximum number of statements allowed per line.
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* @author Kenneth Williams
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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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//------------------------------------------------------------------------------
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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: "layout",
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docs: {
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description: "enforce a maximum number of statements allowed per line",
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category: "Stylistic Issues",
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recommended: false,
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url: "https://eslint.org/docs/rules/max-statements-per-line"
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},
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schema: [
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{
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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: 1,
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default: 1
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}
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},
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additionalProperties: false
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}
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],
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messages: {
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exceed: "This line has {{numberOfStatementsOnThisLine}} {{statements}}. Maximum allowed is {{maxStatementsPerLine}}."
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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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options = context.options[0] || {},
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maxStatementsPerLine = typeof options.max !== "undefined" ? options.max : 1;
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let lastStatementLine = 0,
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numberOfStatementsOnThisLine = 0,
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firstExtraStatement;
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//--------------------------------------------------------------------------
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// Helpers
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//--------------------------------------------------------------------------
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const SINGLE_CHILD_ALLOWED = /^(?:(?:DoWhile|For|ForIn|ForOf|If|Labeled|While)Statement|Export(?:Default|Named)Declaration)$/u;
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/**
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* Reports with the first extra statement, and clears it.
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* @returns {void}
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*/
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function reportFirstExtraStatementAndClear() {
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if (firstExtraStatement) {
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context.report({
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node: firstExtraStatement,
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messageId: "exceed",
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data: {
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numberOfStatementsOnThisLine,
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maxStatementsPerLine,
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statements: numberOfStatementsOnThisLine === 1 ? "statement" : "statements"
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}
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});
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}
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firstExtraStatement = null;
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}
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/**
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* Gets the actual last token of a given node.
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* @param {ASTNode} node A node to get. This is a node except EmptyStatement.
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* @returns {Token} The actual last token.
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*/
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function getActualLastToken(node) {
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return sourceCode.getLastToken(node, astUtils.isNotSemicolonToken);
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}
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/**
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* Addresses a given node.
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* It updates the state of this rule, then reports the node if the node violated this rule.
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* @param {ASTNode} node A node to check.
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* @returns {void}
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*/
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function enterStatement(node) {
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const line = node.loc.start.line;
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/*
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* Skip to allow non-block statements if this is direct child of control statements.
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* `if (a) foo();` is counted as 1.
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* But `if (a) foo(); else foo();` should be counted as 2.
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*/
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if (SINGLE_CHILD_ALLOWED.test(node.parent.type) &&
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node.parent.alternate !== node
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) {
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return;
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}
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// Update state.
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if (line === lastStatementLine) {
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numberOfStatementsOnThisLine += 1;
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} else {
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reportFirstExtraStatementAndClear();
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numberOfStatementsOnThisLine = 1;
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lastStatementLine = line;
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}
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// Reports if the node violated this rule.
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if (numberOfStatementsOnThisLine === maxStatementsPerLine + 1) {
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firstExtraStatement = firstExtraStatement || node;
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}
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}
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/**
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* Updates the state of this rule with the end line of leaving node to check with the next statement.
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* @param {ASTNode} node A node to check.
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* @returns {void}
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*/
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function leaveStatement(node) {
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const line = getActualLastToken(node).loc.end.line;
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// Update state.
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if (line !== lastStatementLine) {
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reportFirstExtraStatementAndClear();
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numberOfStatementsOnThisLine = 1;
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lastStatementLine = line;
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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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BreakStatement: enterStatement,
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ClassDeclaration: enterStatement,
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ContinueStatement: enterStatement,
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DebuggerStatement: enterStatement,
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DoWhileStatement: enterStatement,
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ExpressionStatement: enterStatement,
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ForInStatement: enterStatement,
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ForOfStatement: enterStatement,
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ForStatement: enterStatement,
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FunctionDeclaration: enterStatement,
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IfStatement: enterStatement,
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ImportDeclaration: enterStatement,
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LabeledStatement: enterStatement,
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ReturnStatement: enterStatement,
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SwitchStatement: enterStatement,
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ThrowStatement: enterStatement,
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TryStatement: enterStatement,
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VariableDeclaration: enterStatement,
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WhileStatement: enterStatement,
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WithStatement: enterStatement,
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ExportNamedDeclaration: enterStatement,
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ExportDefaultDeclaration: enterStatement,
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ExportAllDeclaration: enterStatement,
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"BreakStatement:exit": leaveStatement,
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"ClassDeclaration:exit": leaveStatement,
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"ContinueStatement:exit": leaveStatement,
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"DebuggerStatement:exit": leaveStatement,
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"DoWhileStatement:exit": leaveStatement,
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"ExpressionStatement:exit": leaveStatement,
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"ForInStatement:exit": leaveStatement,
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"ForOfStatement:exit": leaveStatement,
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"ForStatement:exit": leaveStatement,
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"FunctionDeclaration:exit": leaveStatement,
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"IfStatement:exit": leaveStatement,
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"ImportDeclaration:exit": leaveStatement,
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"LabeledStatement:exit": leaveStatement,
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"ReturnStatement:exit": leaveStatement,
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"SwitchStatement:exit": leaveStatement,
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"ThrowStatement:exit": leaveStatement,
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"TryStatement:exit": leaveStatement,
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"VariableDeclaration:exit": leaveStatement,
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"WhileStatement:exit": leaveStatement,
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"WithStatement:exit": leaveStatement,
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"ExportNamedDeclaration:exit": leaveStatement,
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"ExportDefaultDeclaration:exit": leaveStatement,
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"ExportAllDeclaration:exit": leaveStatement,
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"Program:exit": reportFirstExtraStatementAndClear
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};
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}
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};
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