148 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			JavaScript
		
	
	
		
			Executable File
		
	
	
	
	
			
		
		
	
	
			148 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			JavaScript
		
	
	
		
			Executable File
		
	
	
	
	
/**
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 * @fileoverview Rule to enforce declarations in program or function body root.
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 * @author Brandon Mills
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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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const validParent = new Set([
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	"Program",
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	"StaticBlock",
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	"ExportNamedDeclaration",
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	"ExportDefaultDeclaration",
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]);
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const validBlockStatementParent = new Set([
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	"FunctionDeclaration",
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	"FunctionExpression",
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	"ArrowFunctionExpression",
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]);
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/**
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 * Finds the nearest enclosing context where this rule allows declarations and returns its description.
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 * @param {ASTNode} node Node to search from.
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 * @returns {string} Description. One of "program", "function body", "class static block body".
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 */
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function getAllowedBodyDescription(node) {
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	let { parent } = node;
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	while (parent) {
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		if (parent.type === "StaticBlock") {
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			return "class static block body";
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		}
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		if (astUtils.isFunction(parent)) {
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			return "function body";
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		}
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		({ parent } = parent);
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	}
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	return "program";
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}
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/** @type {import('../types').Rule.RuleModule} */
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module.exports = {
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	meta: {
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		type: "problem",
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		defaultOptions: ["functions", { blockScopedFunctions: "allow" }],
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		docs: {
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			description:
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				"Disallow variable or `function` declarations in nested blocks",
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			recommended: false,
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			url: "https://eslint.org/docs/latest/rules/no-inner-declarations",
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		},
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		schema: [
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			{
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				enum: ["functions", "both"],
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			},
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			{
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				type: "object",
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				properties: {
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					blockScopedFunctions: {
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						enum: ["allow", "disallow"],
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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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			moveDeclToRoot: "Move {{type}} declaration to {{body}} root.",
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		},
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	},
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	create(context) {
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		const both = context.options[0] === "both";
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		const { blockScopedFunctions } = context.options[1];
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		const sourceCode = context.sourceCode;
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		const ecmaVersion = context.languageOptions.ecmaVersion;
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		/**
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		 * Ensure that a given node is at a program or function body's root.
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		 * @param {ASTNode} node Declaration node to check.
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		 * @returns {void}
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		 */
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		function check(node) {
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			const parent = node.parent;
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			if (
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				parent.type === "BlockStatement" &&
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				validBlockStatementParent.has(parent.parent.type)
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			) {
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				return;
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			}
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			if (validParent.has(parent.type)) {
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				return;
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			}
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			context.report({
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				node,
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				messageId: "moveDeclToRoot",
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				data: {
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					type:
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						node.type === "FunctionDeclaration"
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							? "function"
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							: "variable",
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					body: getAllowedBodyDescription(node),
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				},
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			});
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		}
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		return {
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			FunctionDeclaration(node) {
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				const isInStrictCode = sourceCode.getScope(node).upper.isStrict;
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				if (
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					blockScopedFunctions === "allow" &&
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					ecmaVersion >= 2015 &&
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					isInStrictCode
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				) {
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					return;
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				}
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				check(node);
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			},
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			VariableDeclaration(node) {
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				if (both && node.kind === "var") {
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					check(node);
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				}
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			},
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		};
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	},
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};
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