Lodash best of function
Reduce a collection to a single value by applying a function (a reducer to all collection values)
Useful to create map data structrure from arrays
You want all the keys of an object as array? No problem _.keys!
You have a map and want the inverse (the key becomethe value & vice versa). It is one usage of _.invert
Useful to test if a string is in an array of strings for examples. A sort of inArray function….
Good to produce grouped display, you have an array on object, and it can group them by one of its properties.