105 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			105 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
/**
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 * @fileoverview A rule to disallow duplicate name in class members.
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 * @author Toru Nagashima
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 */
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"use strict";
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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: "problem",
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        docs: {
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            description: "Disallow duplicate class members",
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            recommended: true,
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            url: "https://eslint.org/docs/latest/rules/no-dupe-class-members"
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        },
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        schema: [],
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        messages: {
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            unexpected: "Duplicate name '{{name}}'."
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        }
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    },
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    create(context) {
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        let stack = [];
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        /**
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         * Gets state of a given member name.
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         * @param {string} name A name of a member.
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         * @param {boolean} isStatic A flag which specifies that is a static member.
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         * @returns {Object} A state of a given member name.
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         *   - retv.init {boolean} A flag which shows the name is declared as normal member.
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         *   - retv.get {boolean} A flag which shows the name is declared as getter.
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         *   - retv.set {boolean} A flag which shows the name is declared as setter.
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         */
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        function getState(name, isStatic) {
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            const stateMap = stack[stack.length - 1];
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            const key = `$${name}`; // to avoid "__proto__".
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            if (!stateMap[key]) {
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                stateMap[key] = {
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                    nonStatic: { init: false, get: false, set: false },
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                    static: { init: false, get: false, set: false }
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                };
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            }
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            return stateMap[key][isStatic ? "static" : "nonStatic"];
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        }
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        return {
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            // Initializes the stack of state of member declarations.
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            Program() {
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                stack = [];
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            },
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            // Initializes state of member declarations for the class.
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            ClassBody() {
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                stack.push(Object.create(null));
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            },
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            // Disposes the state for the class.
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            "ClassBody:exit"() {
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                stack.pop();
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            },
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            // Reports the node if its name has been declared already.
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            "MethodDefinition, PropertyDefinition"(node) {
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                const name = astUtils.getStaticPropertyName(node);
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                const kind = node.type === "MethodDefinition" ? node.kind : "field";
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                if (name === null || kind === "constructor") {
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                    return;
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                }
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                const state = getState(name, node.static);
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                let isDuplicate = false;
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                if (kind === "get") {
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                    isDuplicate = (state.init || state.get);
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                    state.get = true;
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                } else if (kind === "set") {
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                    isDuplicate = (state.init || state.set);
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                    state.set = true;
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                } else {
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                    isDuplicate = (state.init || state.get || state.set);
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                    state.init = true;
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                }
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                if (isDuplicate) {
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                    context.report({ node, messageId: "unexpected", data: { name } });
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                }
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            }
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        };
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    }
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};
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