How to group an array of objects by key

Question

Does anyone know of a (lodash if possible too) way to group an array of objects by an object key then create a new array of objects based on the grouping? For example, I hav

Answer 1

You are looking for _.groupBy().

Removing the property you are grouping by from the objects should be trivial if required:

var cars = [{'make':'audi','model':'r8','year':'2012'},{'make':'audi','model':'rs5','year':'2013'},{'make':'ford','model':'mustang','year':'2012'},{'make':'ford','model':'fusion','year':'2015'},{'make':'kia','model':'optima','year':'2012'},];

var grouped = _.groupBy(cars, function(car) {
  return car.make;
});

console.log(grouped);

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As a bonus, you get even nicer syntax with ES6 arrow functions:

const grouped = _.groupBy(cars, car => car.make);