gistfile1.js

// Lets say we have a replica, already stored in the DB and in the live set (I call it - in the scope):

var rep = {
    attrib : 'some_value'
}

// then user mutates it with rep.setAttrib('new_value')

var rep = {
    attrib : 'new_value'
}

// we create a mutation object, which contain a reference to original + mutation data

var mutation = {
    object : rep,
    
    attributeName   : 'attrib',
    oldValue        : 'some_value',
    newValue        : 'new_value'
}

// after some time we have an array of mutations:

[ mut1, mut2, ... ]

// shallow collapse for this array will only give us a changed portion of the graph