Map collection items by properties lodash

Question

Data like this:

[
   {type: "one", ...fields},
   {type: "one", ...fields},
   {type: "two", ...fields}
]

should be converted to this:

{
   one: [...itemsWithType == "one"],
   two: [...itemsWithType == "two"]
}

I know how to do it in vanillas ES5 / ES6.. I am looking for a special lodash command. I am just lost in the docs, and maybe someone can tell me how this preparation is called, that I can notice it.

I am looking for a simple lodash function like

mapByProp(collection, 'type');

Yes, this could be written like this one:

const mapByProp = (array, t) => {
   return array.reduce((m, i) => {
     !m[i[t]] && m[i[t]] = [];
     m[i[t]].push(i);

     return m;
   }, {});
};

But if there is a lodash function, I would love to use it

Answer 1

You can use _.groupBy :

var a = [
   {type: "one", wow: 1},
   {type: "one", wow: 2},
   {type: "two", wow: 3}
];

var result = _.groupBy(a, 'type');