convert array of JSON objects to hash map using lodash

Question

I need to convert

var data = [
{ rel: 'links-A', href: 'url1', id: 0},
{ rel: 'links-A', href: 'url2', id: 1},
{ rel: 'links-B', href: 'url3', id: 2},
{ rel: 'links-B', href: 'url4', id: 3},
];

to a hash map like this:

var converted = {
linksA: [
        {href: 'url1', id: 0},
        {href: 'url2', id: 1}
                 ],
linksB: [
        {href: 'url3', id: 2},
        {href: 'url4', id: 3}
        ],
}

Not sure if it's doable with lodash

Answer 1

First groupBy rel and then map across the keys using mapKeys to remove the hyphen:

var converted = _(data)
    .groupBy('rel')
    .mapKeys( (v, k) => k.replace('-', ''))
    .value();

Answer 2

You don't even have to use lodash if you don't want to. The .reduce array method should be sufficient:

 var data = [ { rel: 'links-A', href: 'url1', id: 0}, { rel: 'links-A', href: 'url2', id: 1}, { rel: 'links-B', href: 'url3', id: 2}, { rel: 'links-B', href: 'url4', id: 3}, ] var converted = data.reduce((final, current) => { var newKey = current.rel.replace("-", ""); if (!final[newKey]) final[newKey] = []; final[newKey].push({href: current.href, id: current.id}); return final; }, {}) console.log(converted)