rename.js

Object.prototype.renameProperty = function (oldName, newName) {
    if (this.hasOwnProperty(oldName)) {
        this[newName] = this[oldName];
        delete this[oldName];
    }
    return this;
};

const mapping = [
  {old: 'something1', new: 'something_else'},
  {old: 'something2', new: 'something_else'},
  {old: 'alice', new: 'bob'}
];

const object1 = {
  something1: 'first prop',
  alice: 'second prop'
};

const object2 = {
  something2: 'first prop',
  alice: 'second prop'
};

function mapProperties (object) {
  mapping.forEach((mapper) => {
    object.renameProperty(mapper.old, mapper.new);
  });  
  console.log(object);
}

(function () {
  mapProperties(object1);
  mapProperties(object2);
})();