eslint-plugin-san/lib/rules/no-duplicate-attributes.js

Official ESLint plugin for San

/**
 * @author Toru Nagashima
 * @copyright 2017 Toru Nagashima. All rights reserved.
 * See LICENSE file in root directory for full license.
 */
'use strict';

/* eslint-disable */

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

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

// ------------------------------------------------------------------------------
// Helpers
// ------------------------------------------------------------------------------

/**
 * Get the name of the given attribute node.
 * @param {VAttribute | VDirective} attribute The attribute node to get.
 * @returns {string | null} The name of the attribute.
 */
function getName(attribute) {
    if (!attribute.directive) {
        return attribute.key.name;
    }
    if (attribute.key.name.name === 'bind') {
        return (
            (attribute.key.argument && attribute.key.argument.type === 'VIdentifier' && attribute.key.argument.name) ||
            null
        );
    }
    return null;
}

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

module.exports = {
    meta: {
        type: 'problem',
        docs: {
            description: 'disallow duplication of attributes',
            categories: ['essential'],
            url: 'https://ecomfe.github.io/eslint-plugin-san/rules/no-duplicate-attributes.html'
        },
        fixable: null,

        schema: [
            {
                type: 'object',
                properties: {
                    allowCoexistClass: {
                        type: 'boolean'
                    },
                    allowCoexistStyle: {
                        type: 'boolean'
                    }
                }
            }
        ]
    },
    /** @param {RuleContext} context */
    create(context) {
        const options = context.options[0] || {};
        const allowCoexistStyle = options.allowCoexistStyle !== false;
        const allowCoexistClass = options.allowCoexistClass !== false;

        /** @type {Set<string>} */
        const directiveNames = new Set();
        /** @type {Set<string>} */
        const attributeNames = new Set();

        /**
         * @param {string} name
         * @param {boolean} isDirective
         */
        function isDuplicate(name, isDirective) {
            if ((allowCoexistStyle && name === 'style') || (allowCoexistClass && name === 'class')) {
                return isDirective ? directiveNames.has(name) : attributeNames.has(name);
            }
            return directiveNames.has(name) || attributeNames.has(name);
        }

        return utils.defineTemplateBodyVisitor(context, {
            VStartTag() {
                directiveNames.clear();
                attributeNames.clear();
            },
            VAttribute(node) {
                const name = getName(node);
                if (name == null) {
                    return;
                }

                if (isDuplicate(name, node.directive)) {
                    context.report({
                        node,
                        loc: node.loc,
                        message: "Duplicate attribute '{{name}}'.",
                        data: {name}
                    });
                }

                if (node.directive) {
                    directiveNames.add(name);
                } else {
                    attributeNames.add(name);
                }
            }
        });
    }
};