Simple object to object mapper

SimpleMapper.js

const _ = require('lodash');

class SimpleMapper  {
    constructor(data) {
        this.data = _.cloneDeep(data);
        this.mappings = [];
        this.result = {};
    }

    addMapping(destination, source, transform = v => v) {
        this.mappings.push({ source, destination, transform }); 
        return this;
    }

    map() {
        this.mappings.forEach(({ destination, source, transform }) => {
            const value = _.isFunction(source) ?
                source.call(this.data) : _.get(this.data, source);

            const transformedValue = _.isFunction(transform) ?
                transform.call(this.data, value) : value;

            _.set(this.result, destination, transformedValue);
        });

        return this.result;
    }
}

// example

const objA = { prop1: 'John', prop2: 'Smith', prop3: { prop5: '35'} };
const mapper = new SimpleMapper(objA);

const toUpper = v => v.toUpperCase();
function getFullName() {
  return `${this.prop1} ${this.prop2}`;
}

const person = mapper
    .addMapping('personal.name', 'prop1', toUpper)
    .addMapping('personal.fullName', getFullName, toUpper)
    .addMapping('age', 'prop3.prop5')
    .map();

console.log(person); // => { personal: { name: 'JOHN', fullName: 'JOHN SMITH' }, age: '35' }