var data = {
'one': {id: 10, name: 'user-10'},
'two': {id: 15, name: 'w-user-15'},
'three': {id: 20, name: 'user-20'},
};
var len = R.pipe(
R.keys,
R.length
)(data);
alert( JSON.stringify(len) );
<script src="//cdn.jsdelivr.net/npm/ramda@latest/dist/ramda.js"></script>