underscore.js - Group objects by property in javascript

Question

How to convert this:

[
    {food: 'apple', type: 'fruit'},
    {food: 'potato', type: 'vegetable'},
    {food: 'banana', type: 'fruit'},
]

into this:

[
    {type: 'fruit', foods: ['apple', 'banana']},
    {type: 'vegetable', foods: ['potato']}
]

using javascript or underscore

Answer 1

Assuming the original list is contained in a variable named list:

_
.chain(list)
.groupBy('type')
.map(function(value, key) {
    return {
        type: key,
        foods: _.pluck(value, 'food')
    }
})
.value();