viewModel.js

'use strict';

const R = require('ramda');
const Rx = require('../ramdaExt');

const concatUnique = (k, l, r) => {
    if(R.equals(l, r))
        return R.flatten([l]);
    return R.flatten([l, r]);
}

const termFor = bindingGroup => {
    if(bindingGroup.length === 0)
        return {};

    const head = R.head(bindingGroup);
    const t = R.pipe(
        R.toPairs,
        R.map(p => {
            return [
                R.slice(1, Infinity, Rx.first(p)),          // remove '?' from SPARQL parameters
                [ R.prop('value', Rx.second(p)) ]           // TODO: add friendly type name back
            ];
        }),
        R.fromPairs)(head);

    return R.mergeWithKey(concatUnique, t, termFor(R.tail(bindingGroup)));
};

const termsFrom = R.pipe(
    R.groupBy(R.path(['?id', 'value'])),
    R.values,
    R.map(termFor));

module.exports = {
    termsFrom,
    termFor
};