Javascript type mapper - transforms properties of an object according to a type definition from string to float, int or boolean

mapper.js

export function mapTypes(map) {
    return (obj) => {
        const newObj = {};
        // eslint-disable-next-line no-restricted-syntax
        for (const key in obj) {
            if (Object.hasOwnProperty.call(obj, key)) {
                let value = obj[key];
                const type = map[key];
                switch (type) {
                    case 'float':
                        value = parseFloat(value);
                        if (!Number.isNaN(value)) {
                            newObj[key] = value;
                        }
                        break;
                    case 'int':
                        value = parseInt(value, 10);
                        if (!Number.isNaN(value)) {
                            newObj[key] = value;
                        }
                        break;
                    case 'bool':
                        if (String(value).toLowerCase() === 'true') {
                            newObj[key] = true;
                        } else if (String(value).toLowerCase() === 'false') {
                            newObj[key] = false;
                        }
                        break;
                    default:
                        newObj[key] = value;
                        break;
                }
            }
        }
        return newObj;
    };
}

mapper.unit.js

/* eslint-env jest */

import { mapTypes } from './mapper';

describe('Mapper', () => {
    const typeMapper = mapTypes({ price: 'float', hours: 'int', used: 'bool' });
    test('Maps float and int types', () => {
        const result = typeMapper({
            price: '100.10',
            hours: '88',
            title: 'Hello',
        });
        expect(result).toEqual({ price: 100.1, hours: 88, title: 'Hello' });
    });
    test('Maps boolean types', () => {
        const result = [
            {
                used: 'true',
            },
            {
                used: 'false',
            },
        ].map(typeMapper);
        expect(result).toEqual([{ used: true }, { used: false }]);
    });
    test('Invalid values are skipped', () => {
        const result = typeMapper({
            price: 'Hello',
            hours: 'Hello',
            used: 'Hello',
            title: 'Hello',
        });
        expect(result).toEqual({ title: 'Hello' });
    });
});