I am looking for a way to filter a map by value instead of key. I have a data set that is modeled as follows in my Angular application: { "85d55e6b-f4bf-47bb-a988-78fdb9650ef0": { is_deleted: false, public_email: "007@example.org", id: "85d55e6b-f4bf-47bb-a988-78fdb9650ef0", modified_at: "2017-09-26T15:35:06.853492Z", social_url: "https://facebook.com/jamesbond007", event_id: "213b01de-da9e-4d19-8e9c-c0dae63e019c", visitor_id: "c3c232ff-1381-4776-a7f2-46c177ecde1c", }, } The keys on these entries are the same as the id field on the entries values. Given several of these entries, I would like to filter and return a new Map() that contains only those entries with a given event_id. Were this an array I would just do the following: function example(eventId: string): Event[] { return array.filter((item: Event) => item.event_id === eventId); } Essentially, I am attempting to replicate the functionality of Array.prototype.map() - just on a Map instead of an Array. I am willing to use Lodash if it will help achieve this in a more succinct way as it is already available in my project. Continue reading...