Skip to content

Latest commit

 

History

History
44 lines (34 loc) · 1.19 KB

datascript.org

File metadata and controls

44 lines (34 loc) · 1.19 KB

Background

If you are unfamiliar with datomic, probably visit that tutorial first.

Setup

Motivation

With clojurescript applications, some people keep their app state in a global atom in the form of a large map. For example:

(def app-state
  {:user-logged-in true
   :secure-token "adslkfj23l4jskdlfj42w5j"
   :email "joe.blow@gmail.com"
   :user-id 1
   :friends [{:user-id 2 :name "sally" :status :active}
             {:user-id 3 :name "bob"}]
   :co-workers [{:user-id 2 :name "sally" :status :active]})

Why on earth would we ever want to have a small database on the client side? Seems like overkill right? Well say in our above app, “sally” signs off and is no longer active. I have to update that in two places, there is no master record.

(def app-state
  {:user-logged-in true
   :secure-token "adslkfj23l4jskdlfj42w5j"
   :email "joe.blow@gmail.com"
   :user-id 1
   :users [{:user-id 2 :name "sally" :active :away}]
   :friends [2 3]
   :co-workers [2])

I wanted to pay “sally” back the 50.50 I owed her. Since I’m storing that in two locations, I have to make sure I update both locations.