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re-frame.substrate.plain-atom

Use this namespace to run re-frame2 with no view layer: JVM and Node tests, scripts, and headless hosts. It provides the adapter you pass to rf/init!, or to a test fixture as its :adapter. app-db lives in a plain clojure.core/atom and nothing renders, so a suite runs on the JVM or Node with no React.

It ships in core, day8/re-frame2, so it needs no extra dependency. It is a .cljc namespace and loads on both hosts.

(:require [re-frame.core :as rf]
          [re-frame.test-support :as ts]
          [re-frame.substrate.plain-atom :as plain-atom])

(rf/init! plain-atom/adapter)   ;; a script or headless host, once at boot

;; a test namespace: the fixture installs it before each test
(use-fixtures :each (ts/make-reset-runtime-fixture {:adapter plain-atom/adapter}))

Events, effects and subscriptions behave as they do under any other adapter. Subscriptions are not cached: a derived value recomputes on every read. That suits tests and one-shot reads; an app that renders live installs a React or Fresco adapter instead. Testing builds a suite on it.

Adapter spec

adapter

  • Kind: var (map)
  • Signature: 
    {:kind                      :rf.adapter/plain-atom
 :make-state-container      …
 :read-container            …
 :replace-container!        …
 :subscribe-container       …
 :make-derived-value        …
 :render                    …
 :render-to-string          …
 :register-context-provider …
 :dispose-adapter!          …}
;; on CLJS it also carries :add-on-dispose! and :dispose!
  • Description: The adapter map you pass to rf/init! to install the headless substrate; (:kind (rf/current-adapter)) reads :rf.adapter/plain-atom.
    • Installation is explicit: there is no default adapter, and loading this namespace installs nothing.
    • A derived value caches nothing. Each watcher watches its sources while it is attached and is notified when the computed value changes by =.
    • Nothing renders. Its :render slot throws :rf.error/render-on-headless-adapter, and it has no :flush-render!, so ts/flush-views! runs its function and commits nothing.
    • For server rendering, install re-frame.ssr's adapter.
  • Example: 
    (rf/init! plain-atom/adapter)

See also