Ramda and Lenses

simple-lens.js

var ana = new Person('Ana', 'Gonzalez');
var firstnameLens = R.lensProp('firstname');

// read firtstname
R.view(firstnameLens, ana); //-> 'Ana'           

// transform firstname to upper case
R.over(firstnameLens, R.toUpper, ana); //-> 'ANA'

// set firstname (creates a branch new object)
var olivia = R.set(firstnameLens, 'Olivia', ana)); //-> new Person('Olivia', 'Gonzalez')