eslint-plugin-san/lib/rules/no-template-shadow.js

Official ESLint plugin for San

/**
 * @fileoverview Disallow variable declarations from shadowing variables declared in the outer scope.
 * @author Armano
 */
'use strict';

/* eslint-disable */

// ------------------------------------------------------------------------------
// Requirements
// ------------------------------------------------------------------------------

const utils = require('../utils');

/**
 * @typedef {import('../utils').GroupName} GroupName
 */

// ------------------------------------------------------------------------------
// Rule Definition
// ------------------------------------------------------------------------------

/** @type {GroupName[]} */
const GROUP_NAMES = ['dataTypes', 'computed', 'initData'];

module.exports = {
    meta: {
        type: 'suggestion',
        docs: {
            description: 'disallow variable declarations from shadowing variables declared in the outer scope',
            categories: ['strongly-recommended'],
            url: 'https://ecomfe.github.io/eslint-plugin-san/rules/no-template-shadow.html'
        },
        fixable: null,
        schema: []
    },
    /** @param {RuleContext} context */
    create(context) {
        /** @type {Set<string>} */
        const jsVars = new Set();

        /**
         * @typedef {object} ScopeStack
         * @property {ScopeStack | null} parent
         * @property {Identifier[]} nodes
         */
        /** @type {ScopeStack | null} */
        let scopeStack = null;

        // ----------------------------------------------------------------------
        // Public
        // ----------------------------------------------------------------------

        return utils.defineTemplateBodyVisitor(
            context,
            {
                /** @param {VElement} node */
                VElement(node) {
                    scopeStack = {
                        parent: scopeStack,
                        nodes: scopeStack
                            ? scopeStack.nodes.slice() // make copy
                            : []
                    };
                    if (node.variables) {
                        for (const variable of node.variables) {
                            const varNode = variable.id;
                            const name = varNode.name;
                            if (scopeStack.nodes.some(node => node.name === name) || jsVars.has(name)) {
                                context.report({
                                    node: varNode,
                                    loc: varNode.loc,
                                    message: "Variable '{{name}}' is already declared in the upper scope.",
                                    data: {
                                        name
                                    }
                                });
                            } else {
                                scopeStack.nodes.push(varNode);
                            }
                        }
                    }
                },
                'VElement:exit'() {
                    scopeStack = scopeStack && scopeStack.parent;
                }
            },
            utils.executeOnSan(context, obj => {
                const properties = Array.from(utils.iterateProperties(obj, new Set(GROUP_NAMES)));
                for (const node of properties) {
                    jsVars.add(node.name);
                }

                // for funtion not in methods. modify by kidnes
                if (Array.isArray(obj.properties)) {
                    for (const item of obj.properties) {
                        if (item.type !== 'Property') {
                            continue;
                        }
    
                        const name = utils.getStaticPropertyName(item);
                        if (!name) continue;
    
                        jsVars.add(name);
                    }
                }
            })
        );
    }
};