array/toLookup

[shannonmoeller]

Converts an array to an object indexed by a particular key.

var records = [
    { id: 'foo', greeting: 'hi' },
    { id: 'bar', greeting: 'howdy' },
    { id: 'baz', greeting: 'sup' }
];
var recordsIndex = records.reduce(toLookup('id'), {});
// recordsIndex === {
//     foo: { id: 'foo', greeting: 'hi' },
//     bar: { id: 'bar', greeting: 'howdy' },
//     baz: { id: 'baz', greeting: 'sup' }
// };

[shannonmoeller]

Multiple args for deep index, a la plucks.

https://github.com/shannonmoeller/mtil/issues/1#issuecomment-41986348

[nickstark]

What if lookups are not unique? Make an array?

Maybe we want a separate groupsBy or something that will deal with this.

[nickstark]

It also seems like this function would never be used outside of reduce due to its funky arguments signature. Maybe not a big deal, idk.

[shannonmoeller]

We could create the object if it doesn't exist, so that the signature is consistent:

records.reduce(toLookup('id'));