150 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			150 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
/**
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 * @fileoverview Disallow Labeled Statements
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 * @author Nicholas C. Zakas
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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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/** @type {import('../shared/types').Rule} */
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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: "Disallow labeled statements",
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            recommended: false,
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            url: "https://eslint.org/docs/latest/rules/no-labels"
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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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                    allowLoop: {
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                        type: "boolean",
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                        default: false
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                    },
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                    allowSwitch: {
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                        type: "boolean",
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                        default: false
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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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            unexpectedLabel: "Unexpected labeled statement.",
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            unexpectedLabelInBreak: "Unexpected label in break statement.",
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            unexpectedLabelInContinue: "Unexpected label in continue statement."
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        }
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    },
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    create(context) {
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        const options = context.options[0];
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        const allowLoop = options && options.allowLoop;
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        const allowSwitch = options && options.allowSwitch;
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        let scopeInfo = null;
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        /**
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         * Gets the kind of a given node.
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         * @param {ASTNode} node A node to get.
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         * @returns {string} The kind of the node.
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         */
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        function getBodyKind(node) {
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            if (astUtils.isLoop(node)) {
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                return "loop";
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            }
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            if (node.type === "SwitchStatement") {
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                return "switch";
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            }
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            return "other";
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        }
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        /**
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         * Checks whether the label of a given kind is allowed or not.
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         * @param {string} kind A kind to check.
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         * @returns {boolean} `true` if the kind is allowed.
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         */
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        function isAllowed(kind) {
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            switch (kind) {
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                case "loop": return allowLoop;
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                case "switch": return allowSwitch;
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                default: return false;
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            }
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        }
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        /**
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         * Checks whether a given name is a label of a loop or not.
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         * @param {string} label A name of a label to check.
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         * @returns {boolean} `true` if the name is a label of a loop.
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         */
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        function getKind(label) {
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            let info = scopeInfo;
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            while (info) {
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                if (info.label === label) {
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                    return info.kind;
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                }
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                info = info.upper;
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            }
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            /* c8 ignore next */
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            return "other";
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        }
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        //--------------------------------------------------------------------------
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        // Public
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        //--------------------------------------------------------------------------
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        return {
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            LabeledStatement(node) {
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                scopeInfo = {
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                    label: node.label.name,
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                    kind: getBodyKind(node.body),
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                    upper: scopeInfo
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                };
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            },
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            "LabeledStatement:exit"(node) {
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                if (!isAllowed(scopeInfo.kind)) {
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                    context.report({
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                        node,
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                        messageId: "unexpectedLabel"
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                    });
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                }
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                scopeInfo = scopeInfo.upper;
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            },
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            BreakStatement(node) {
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                if (node.label && !isAllowed(getKind(node.label.name))) {
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                    context.report({
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                        node,
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                        messageId: "unexpectedLabelInBreak"
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                    });
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                }
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            },
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            ContinueStatement(node) {
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                if (node.label && !isAllowed(getKind(node.label.name))) {
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                    context.report({
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                        node,
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                        messageId: "unexpectedLabelInContinue"
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                    });
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                }
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            }
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        };
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    }
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};
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