no-new-wrappers.js

/**
 * @fileoverview Rule to flag when using constructor for wrapper objects
 * @author Ilya Volodin
 */

"use strict";

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

const { getVariableByName } = require("./utils/ast-utils");

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

/** @type {import('../shared/types').Rule} */
module.exports = {
    meta: {
        type: "suggestion",

        docs: {
            description: "Disallow `new` operators with the `String`, `Number`, and `Boolean` objects",
            recommended: false,
            url: "https://eslint.org/docs/latest/rules/no-new-wrappers"
        },

        schema: [],

        messages: {
            noConstructor: "Do not use {{fn}} as a constructor."
        }
    },

    create(context) {
        const { sourceCode } = context;

        return {

            NewExpression(node) {
                const wrapperObjects = ["String", "Number", "Boolean"];
                const { name } = node.callee;

                if (wrapperObjects.includes(name)) {
                    const variable = getVariableByName(sourceCode.getScope(node), name);

                    if (variable && variable.identifiers.length === 0) {
                        context.report({
                            node,
                            messageId: "noConstructor",
                            data: { fn: name }
                        });
                    }
                }
            }
        };

    }
};