diff --git a/.gitignore b/.gitignore
index 92502870..76f17ade 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,5 +22,11 @@ pom.xml
 pom.xml.asc
 /.cljs_node_repl/
 /.cljs_rhino_repl/
-/release-js/datomish.js
-/release-js/datomish.bare.js
+/release-browser
+/release-browser/datomish.js
+/release-browser/datomish.bare.js
+/release-node
+/release-node/datomish.js
+/release-node/datomish.bare.js
+/addon/datomish-test.xpi
+/addon/datomish.js
diff --git a/addon/README.md b/addon/README.md
new file mode 100644
index 00000000..85643d4f
--- /dev/null
+++ b/addon/README.md
@@ -0,0 +1,2 @@
+#Datomish Test
+An example add-on that loads Datomish on top of Sqlite.jsm.
\ No newline at end of file
diff --git a/addon/index.js b/addon/index.js
new file mode 100644
index 00000000..765cb243
--- /dev/null
+++ b/addon/index.js
@@ -0,0 +1,15 @@
+var self = require("sdk/self");
+
+console.log("Datomish Test");
+console.log("This: " + this);
+
+var datomish = require("datomish.js");
+datomish.open("/tmp/foobar.db").then(function (db) {
+  console.log("Got " + db);
+  try {
+    db.close();
+    console.log("Closed.");
+  } catch (e) {
+    console.log("Couldn't close: " + e);
+  }
+});
diff --git a/addon/package.json b/addon/package.json
new file mode 100644
index 00000000..6a190546
--- /dev/null
+++ b/addon/package.json
@@ -0,0 +1,15 @@
+{
+  "title": "Datomish Test",
+  "name": "datomish-test",
+  "version": "0.0.1",
+  "description": "An example add-on that loads Datomish on top of Sqlite.jsm.",
+  "main": "index.js",
+  "author": "Richard Newman <rnewman@mozilla.com>",
+  "engines": {
+    "firefox": ">=48.0a1"
+  },
+  "license": "MPL-2.0",
+  "keywords": [
+    "jetpack"
+  ]
+}
diff --git a/project.clj b/project.clj
index c68cd5b2..72b5b9c1 100644
--- a/project.clj
+++ b/project.clj
@@ -3,7 +3,7 @@
   :url "https://github.com/mozilla/datomish"
   :license {:name "Mozilla Public License Version 2.0"
             :url  "https://github.com/mozilla/datomish/blob/master/LICENSE"}
-  :dependencies [[org.clojure/clojurescript "1.9.89"]
+  :dependencies [[org.clojure/clojurescript "1.9.229"]
                  [org.clojure/clojure "1.8.0"]
                  [org.clojure/core.async "0.2.385"]
                  [datascript "0.15.1"]
@@ -11,37 +11,89 @@
                  [com.taoensso/tufte "1.0.2"]
                  [jamesmacaulay/cljs-promises "0.1.0"]]
 
-  :cljsbuild {:builds {:release {
-                                 :source-paths   ["src"]
-                                 :assert         false
-                                 :compiler       {:output-to      "release-js/datomish.bare.js"
-                                                  :optimizations  :advanced
-                                                  :pretty-print   false
-                                                  :elide-asserts  true
-                                                  :output-wrapper false
-                                                  :parallel-build true}
-                                 :notify-command ["release-js/wrap_bare.sh"]}
-                       :advanced {:source-paths ["src"]
-                                  :compiler     {:output-to            "target/advanced/datomish.js"
-                                                 :optimizations        :advanced
-                                                 :source-map           "target/advanced/datomish.js.map"
-                                                 :pretty-print         true
-                                                 :recompile-dependents true
-                                                 :parallel-build       true
-                                                 }}
-                       :test {
-                              :source-paths ["src" "test"]
-                              :compiler     {:output-to            "target/test/datomish.js"
-                                             :output-dir           "target/test"
-                                             :main                 datomish.test
-                                             :optimizations        :none
-                                             :source-map           true
-                                             :recompile-dependents true
-                                             :parallel-build       true
-                                             :target               :nodejs
-                                             }}
-                       }
-              }
+  :cljsbuild {:builds
+              {
+               :release-node
+               {
+                :source-paths   ["src-node" "src"]
+                :assert         false
+                :compiler
+                {
+                 :elide-asserts  true
+                 :hashbang       false
+                 :language-in    :ecmascript5
+                 :language-out   :ecmascript5
+                 :optimizations  :advanced
+                 :output-dir     "release-node"
+                 :output-to      "release-node/datomish.bare.js"
+                 :output-wrapper false
+                 :parallel-build true
+                 :pretty-print   false
+                 :target         :nodejs
+                 }
+                :notify-command ["release-node/wrap_bare.sh"]}
+
+               :release-browser
+               ;; Release builds for use in Firefox must:
+               ;; * Use :optimizations > :none, so that a single file is generated
+               ;;   without a need to import Closure's own libs.
+               ;; * Be wrapped, so that a CommonJS module is produced.
+               ;; * Have a preload script that defines what `println` does.
+               ;;
+               ;; There's no point in generating a source map -- it'll be wrong
+               ;; due to wrapping.
+               {
+                :source-paths   ["src-browser" "src"]
+                :assert         false
+                :compiler
+                {
+                 :elide-asserts  true
+                 :externs        ["src-browser/externs.js"]
+                 :language-in    :ecmascript5
+                 :language-out   :ecmascript5
+                 :optimizations  :advanced
+                 :output-dir     "release-browser"
+                 :output-to      "release-browser/datomish.bare.js"
+                 :output-wrapper false
+                 :parallel-build true
+                 :preloads       [datomish.preload]
+                 :pretty-print   true
+                 :pseudo-names   true
+                 :static-fns     true
+                 }
+                :notify-command ["release-browser/wrap_bare.sh"]}
+
+               :advanced
+               {:source-paths ["src-node" "src"]
+                :compiler
+                {
+                 :language-in    :ecmascript5
+                 :language-out   :ecmascript5
+                 :output-dir     "target/advanced"
+                 :output-to      "target/advanced/datomish.js"
+                 :optimizations  :advanced
+                 :parallel-build true
+                 :pretty-print   true
+                 :source-map     "target/advanced/datomish.js.map"
+                 :target         :nodejs
+                 }}
+
+               :test
+               {
+                :source-paths ["src-node" "src" "test"]
+                :compiler
+                {
+                 :language-in    :ecmascript5
+                 :language-out   :ecmascript5
+                 :main           datomish.test
+                 :optimizations  :none
+                 :output-dir     "target/test"
+                 :output-to      "target/test/datomish.js"
+                 :parallel-build true
+                 :source-map     true
+                 :target         :nodejs
+                 }}
+               }}
 
   :profiles {:dev {:dependencies [[cljsbuild "1.1.3"]
                                   [tempfile "0.2.0"]
@@ -59,7 +111,26 @@
 
   :doo {:build "test"}
 
-  :clean-targets ^{:protect false} ["target"
-                                    "release-js/datomish.bare.js"
-                                    "release-js/datomish.js"]
+  :clean-targets ^{:protect false}
+            [
+             "target"
+             "release-node/cljs/"
+             "release-node/cljs_promises/"
+             "release-node/clojure/"
+             "release-node/datascript/"
+             "release-node/datomish/"
+             "release-node/honeysql/"
+             "release-node/taoensso/"
+             "release-node/datomish.bare.js"
+             "release-node/datomish.js"
+             "release-browser/cljs/"
+             "release-browser/cljs_promises/"
+             "release-browser/clojure/"
+             "release-browser/datascript/"
+             "release-browser/datomish/"
+             "release-browser/honeysql/"
+             "release-browser/taoensso/"
+             "release-browser/datomish.bare.js"
+             "release-browser/datomish.js"
+             ]
   )
diff --git a/release-js/README.md b/release-browser/README.md
similarity index 100%
rename from release-js/README.md
rename to release-browser/README.md
diff --git a/release-js/test_include_node.js b/release-browser/test_include_node.js
similarity index 100%
rename from release-js/test_include_node.js
rename to release-browser/test_include_node.js
diff --git a/release-browser/wrap_bare.sh b/release-browser/wrap_bare.sh
new file mode 100755
index 00000000..6d5ae26a
--- /dev/null
+++ b/release-browser/wrap_bare.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+
+set -e
+
+(cat release-browser/wrapper.prefix; cat release-browser/datomish.bare.js; cat release-browser/wrapper.suffix) > release-browser/datomish.js
+
+echo "Packed release-browser/datomish.js"
diff --git a/release-browser/wrapper.prefix b/release-browser/wrapper.prefix
new file mode 100644
index 00000000..5693f1c6
--- /dev/null
+++ b/release-browser/wrapper.prefix
@@ -0,0 +1,34 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Datomish 0.1.0-SNAPSHOT
+
+(function (definition) {
+    // This file will function properly as a <script> tag, or a module
+    // using CommonJS and NodeJS or RequireJS module formats.
+
+    // Wrapper gratefully adapted from:
+    // https://github.com/kriskowal/q/blob/v1/q.js
+    // https://github.com/swannodette/mori/blob/master/support/wrapper.js
+    // https://github.com/tonsky/datascript/blob/master/release-js/wrapper.js
+
+    // CommonJS
+    if (typeof exports === "object") {
+        module.exports = definition();
+
+    // RequireJS
+    } else if (typeof define === "function" && define.amd) {
+        define(definition);
+
+    // <script>
+    } else {
+        datomish = definition();
+    }
+})(function () {
+    return function () {
+
+// Monkeypatch setTimeout so that the Closure Compiler
+// output can use it in a Sandbox context.
+var { setTimeout } = require("sdk/timers");
+this.setTimeout = setTimeout;
diff --git a/release-js/wrapper.suffix b/release-browser/wrapper.suffix
similarity index 100%
rename from release-js/wrapper.suffix
rename to release-browser/wrapper.suffix
diff --git a/release-js/wrap_bare.sh b/release-js/wrap_bare.sh
deleted file mode 100755
index 0256ad22..00000000
--- a/release-js/wrap_bare.sh
+++ /dev/null
@@ -1,7 +0,0 @@
-#!/bin/sh
-
-set -e
-
-(cat release-js/wrapper.prefix; cat release-js/datomish.bare.js; cat release-js/wrapper.suffix) > release-js/datomish.js
-
-echo "Packed release-js/datomish.js"
diff --git a/release-node/README.md b/release-node/README.md
new file mode 100644
index 00000000..f31204bf
--- /dev/null
+++ b/release-node/README.md
@@ -0,0 +1,5 @@
+# Datomish
+
+Datomish is a persistent, embedded knowledge base. It's written in ClojureScript, and draws heavily on [DataScript](https://github.com/tonsky/datascript) and [Datomic](http://datomic.com).
+
+For more info, check out the [project page](https://github.com/mozila/datomish).
diff --git a/release-node/test_include_node.js b/release-node/test_include_node.js
new file mode 100644
index 00000000..683261cd
--- /dev/null
+++ b/release-node/test_include_node.js
@@ -0,0 +1,2 @@
+var d = require('./datomish');
+console.log(d.q("[:find ?e ?v :where [?e \"name\" ?v] {:x :y}]"));
diff --git a/release-node/wrap_bare.sh b/release-node/wrap_bare.sh
new file mode 100755
index 00000000..13707e8f
--- /dev/null
+++ b/release-node/wrap_bare.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+
+set -e
+
+(cat release-node/wrapper.prefix && cat release-node/datomish.bare.js && cat release-node/wrapper.suffix) > release-node/datomish.js
+
+echo "Packed release-node/datomish.js"
diff --git a/release-js/wrapper.prefix b/release-node/wrapper.prefix
similarity index 100%
rename from release-js/wrapper.prefix
rename to release-node/wrapper.prefix
diff --git a/release-node/wrapper.suffix b/release-node/wrapper.suffix
new file mode 100644
index 00000000..4a9569b7
--- /dev/null
+++ b/release-node/wrapper.suffix
@@ -0,0 +1,6 @@
+
+        ;return this.datomish.js;
+
+    }.call({});
+
+});
diff --git a/src-browser/datomish/core.cljs b/src-browser/datomish/core.cljs
new file mode 100644
index 00000000..37be3214
--- /dev/null
+++ b/src-browser/datomish/core.cljs
@@ -0,0 +1,13 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+(ns datomish.core
+  (:require
+     [honeysql.format :as sql]
+     [datomish.db :as db]
+     [datomish.db-factory :as db-factory]
+     [datomish.js-sqlite :as js-sqlite]
+     [datomish.sqlite :as sqlite]
+     [datomish.transact :as transact]))
+
diff --git a/src-browser/datomish/js_sqlite.cljs b/src-browser/datomish/js_sqlite.cljs
new file mode 100644
index 00000000..095652e3
--- /dev/null
+++ b/src-browser/datomish/js_sqlite.cljs
@@ -0,0 +1,20 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+(ns datomish.js-sqlite
+  (:require
+   [datomish.sqlite :as s]
+   [datomish.js-util :refer [is-node?]]
+   [datomish.sqlitejsm-sqlite :as sqlitejsm-sqlite]))
+
+(def open sqlitejsm-sqlite/open)
+
+(extend-protocol s/ISQLiteConnectionFactory
+  string
+  (<sqlite-connection [path]
+    (open path))
+
+  object
+  (<sqlite-connection [tempfile]
+    (open (.-name tempfile))))
diff --git a/src-browser/datomish/preload.cljs b/src-browser/datomish/preload.cljs
new file mode 100644
index 00000000..6730510d
--- /dev/null
+++ b/src-browser/datomish/preload.cljs
@@ -0,0 +1,8 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+(ns datomish.preload)
+
+(enable-console-print!)
+(println "Console printing enabled.")
diff --git a/src-browser/datomish/sqlitejsm_sqlite.cljs b/src-browser/datomish/sqlitejsm_sqlite.cljs
new file mode 100644
index 00000000..88694797
--- /dev/null
+++ b/src-browser/datomish/sqlitejsm_sqlite.cljs
@@ -0,0 +1,57 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+(ns datomish.sqlitejsm-sqlite
+  (:require
+   [cljs-promises.async]
+   [datomish.sqlite :as s]))
+
+(def sqlite (.import (aget (js/require "chrome") "Cu") "resource://gre/modules/Sqlite.jsm"))
+
+(println "sqlite is" (pr-str sqlite))
+
+;; mozIStorageRow instances expose two methods: getResultByIndex and getResultByName.
+;; Our code expects to treat rows as associative containers, from keyword to value.
+;; So we implement ILookup (which has a different signature for ClojureScript than
+;; Clojure!), hope that we handle nil/NULL correctly, and switch between integers
+;; and keywords.
+(deftype
+  StorageRow
+  [row]
+
+  ILookup
+  (-lookup [o k]
+    (-lookup o k nil))
+
+  (-lookup [o k not-found]
+    (or (if (integer? k)
+          (.getResultByIndex row k)
+          (.getResultByName row (clj->js (name k))))
+        not-found)))
+
+(defrecord SQLite3Connection [db]
+  s/ISQLiteConnection
+  (-execute!
+    [db sql bindings]
+    (cljs-promises.async/pair-port
+      (.execute (.-db db) sql (or (clj->js bindings) #js []))))
+
+  (-each
+    [db sql bindings row-cb]
+    (let [cb (fn [row]
+               (row-cb (StorageRow. row)))]
+      (cljs-promises.async/pair-port
+        (.execute (.-db db) sql (or (clj->js bindings) #js []) (when row-cb cb)))))
+
+  (close
+    [db]
+    (cljs-promises.async/pair-port
+      (.close (.-db db)))))
+
+(defn open
+  [path & {:keys [mode] :or {mode 6}}]
+  (cljs-promises.async/pair-port
+    (->
+      (.openConnection (aget sqlite "Sqlite") (clj->js {:path path :sharedMemoryCache false}))
+      (.then ->SQLite3Connection))))
diff --git a/src-browser/externs.js b/src-browser/externs.js
new file mode 100644
index 00000000..a39b1a03
--- /dev/null
+++ b/src-browser/externs.js
@@ -0,0 +1,33 @@
+var SqliteStatic = {};
+
+/**
+ * @param {Object} options
+ * @return {Promise.<Sqlite>}
+ */
+SqliteStatic.openConnection = function (options) {}
+
+var Sqlite = {}
+
+/**
+ * @param {string} sql
+ * @param {Array} bindings
+ * @return {Promise}
+ */
+Sqlite.execute = function (sql, bindings) {}
+
+/**
+ * @return {Promise}
+ */
+Sqlite.close = function() {}
+
+var StorageRow = {};
+
+/**
+ * @param {string} index
+ */
+StorageRow.getResultByIndex = function (index) {}
+
+/**
+ * @param {string} name
+ */
+StorageRow.getResultByName = function (name) {}
diff --git a/src/datomish/core.cljs b/src-node/datomish/core.cljs
similarity index 100%
rename from src/datomish/core.cljs
rename to src-node/datomish/core.cljs
diff --git a/src-node/datomish/js_sqlite.cljs b/src-node/datomish/js_sqlite.cljs
new file mode 100644
index 00000000..40f289ec
--- /dev/null
+++ b/src-node/datomish/js_sqlite.cljs
@@ -0,0 +1,20 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+(ns datomish.js-sqlite
+  (:require
+   [datomish.sqlite :as s]
+   [datomish.js-util :refer [is-node?]]
+   [datomish.promise-sqlite :as promise-sqlite]))
+
+(def open promise-sqlite/open)
+
+(extend-protocol s/ISQLiteConnectionFactory
+  string
+  (<sqlite-connection [path]
+    (open path))
+
+  object ;; TODO: narrow this to the result of node-tempfile/tempfile.
+  (<sqlite-connection [tempfile]
+    (open (.-name tempfile))))
diff --git a/src/datomish/node_tempfile.cljs b/src-node/datomish/node_tempfile.cljs
similarity index 100%
rename from src/datomish/node_tempfile.cljs
rename to src-node/datomish/node_tempfile.cljs
diff --git a/src/datomish/node_tempfile_macros.cljc b/src-node/datomish/node_tempfile_macros.cljc
similarity index 100%
rename from src/datomish/node_tempfile_macros.cljc
rename to src-node/datomish/node_tempfile_macros.cljc
diff --git a/src/datomish/promise_sqlite.cljs b/src-node/datomish/promise_sqlite.cljs
similarity index 81%
rename from src/datomish/promise_sqlite.cljs
rename to src-node/datomish/promise_sqlite.cljs
index 09adf895..539fd5da 100644
--- a/src/datomish/promise_sqlite.cljs
+++ b/src-node/datomish/promise_sqlite.cljs
@@ -35,12 +35,3 @@
     (->
       (.open sqlite.DB path (clj->js {:mode mode}))
       (.then ->SQLite3Connection))))
-
-(extend-protocol s/ISQLiteConnectionFactory
-  string
-  (<sqlite-connection [path]
-    (open path))
-
-  object ;; TODO: narrow this to the result of node-tempfile/tempfile.
-  (<sqlite-connection [tempfile]
-    (open (.-name tempfile))))
diff --git a/src/datomish/exec_repl.cljc b/src/datomish/exec_repl.cljc
deleted file mode 100644
index 66f2bfcc..00000000
--- a/src/datomish/exec_repl.cljc
+++ /dev/null
@@ -1,111 +0,0 @@
-;; This Source Code Form is subject to the terms of the Mozilla Public
-;; License, v. 2.0. If a copy of the MPL was not distributed with this
-;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-(ns datomish.exec-repl
-  #?(:cljs
-     (:require-macros
-      [datomish.util :refer [while-let]]
-      [datomish.pair-chan :refer [go-pair <?]]
-      [cljs.core.async.macros :refer [go]]))
-  (:require
-     [datomish.db-factory]
-     [datomish.db :as db]
-     [datomish.sqlite :as s]
-     [datomish.sqlite-schema :as ss]
-     [datomish.query :as dq]
-     #?@(:clj
-           [[datomish.jdbc-sqlite]
-            [datomish.pair-chan :refer [go-pair <?]]
-            [datomish.util :refer [while-let]]
-            [clojure.core.async :refer [<!]]])
-     #?@(:cljs
-           [[datomish.promise-sqlite]
-            [datomish.pair-chan]
-            [datomish.util]
-            [cljs.core.async :refer [<!]]])))
-
-#?(:clj
-   (defn pair-channel->lazy-seq
-     "Returns a blocking lazy sequence of items taken from the provided channel."
-     [channel]
-     (lazy-seq
-       (when-let [v (clojure.core.async/<!! channel)]
-         (if (second v)
-           (cons v nil)
-           (cons v (pair-channel->lazy-seq channel)))))))
-
-#?(:clj
-(defn run-to-pair-seq
-  "Given an open database, returns a lazy sequence of results.
-   When fully consumed, underlying resources will be released."
-  [db find]
-  (pair-channel->lazy-seq (db/<?run db find))))
-
-#_
-(defn xxopen []
-    (datomish.pair-chan/go-pair
-      (let [d (datomish.pair-chan/<? (s/<sqlite-connection "/tmp/import.sqlite"))]
-        (clojure.core.async/<!! (ss/<ensure-current-version d))
-        (def db d))))
-
-;; With an open DB…
-#_(run-to-pair-seq
-    db
-    '[:find ?page :in $ :where [?page :page/starred true ?t]])
-
-;; In a Clojure REPL with no open DB…
-#_(clojure.core.async/<!!
-    (datomish.exec-repl/<open-and-run-to-seq-promise
-      "/tmp/foo.sqlite"
-      '[:find ?page :in $ :where [?page :page/starred true ?t]]))
-
-#_(require 'datomish.exec-repl)
-#_(in-ns 'datomish.exec-repl)
-#_
-(go-pair
-  (let [connection (<? (s/<sqlite-connection "/tmp/bigport.db"))
-        d (<? (datomish.db-factory/<db-with-sqlite-connection connection))]
-    (def db d)))
-
-#_
-(go-pair
-  (println (count (first (time
-    (<! (db/<?q db
-                '[:find ?url ?title :in $ :where
-                  [?page :page/visitAt ?v] [(> ?v 1438748166567751)] [?page :page/title ?title] [?page :page/url ?url] ] {})))))))
-
-
-#_
-(go-pair
-  (let [connection (<? (s/<sqlite-connection "/tmp/foo.sqlite"))
-        dd (<? (datomish.db-factory/<db-with-sqlite-connection connection))]
-    (def *db* dd)))
-#_
-(clojure.core.async/<!!
-(go-pair
-(let [now -1
-      forms (mapcat (fn [i]
-                      (map (fn [j]
-                             [:db/add i :x j true])
-                           (range 1000 (* i 2000) i)))
-                    (range 1 10))]
-  (println "Adding" (count forms) "forms")
-  (<? (transact/<transact! *db* forms nil now)))))
-
-#_
-(go-pair
-  (let [connection (<? (s/<sqlite-connection "/tmp/foo.sqlite"))
-        dd (<? (db/<with-sqlite-connection connection))]
-    (println
-       (count
-         (<? (db/<?q dd
-                     '[:find ?e ?v :in $ :where
-                       [?e :x ?v]
-                       #_[(> ?v 1000)]] {}))))))
-
-(dq/parse '[:find ?entity ?tx ?score
- :in $ ?search
- :where [(foobar $ :artist/name ?search) [[?entity _ ?tx ?score]]]])
-
-(honeysql.core/format {:select [:?foo] :from [:foo] :where [:match :foo.x "Bar"]})
diff --git a/src/datomish/js.cljs b/src/datomish/js.cljs
index c42dd25e..c67f7854 100644
--- a/src/datomish/js.cljs
+++ b/src/datomish/js.cljs
@@ -1,11 +1,47 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
 (ns datomish.js
   (:refer-clojure :exclude [])
+  (:require-macros
+     [datomish.pair-chan :refer [go-pair <?]])
   (:require
-   [datomish.core :as d]
-   [cljs.reader]))
+     [cljs.core.async :as a :refer [take! <! >!]]
+     [cljs.reader]
+     [cljs-promises.core :refer [promise]]
+     [datomish.db :as db]
+     [datomish.db-factory :as db-factory]
+     [datomish.pair-chan]
+     [datomish.sqlite :as sqlite]
+     [datomish.js-sqlite :as js-sqlite]
+     [datomish.transact :as transact]))
+
+(defn- take-pair-as-promise! [ch]
+  ;; Just like take-as-promise!, but aware that it's handling a pair channel.
+  (promise
+    (fn [resolve reject]
+      (letfn [(split-pair [[v e]]
+                (if e
+                  (reject e)
+                  (resolve v)))]
+        (cljs.core.async/take! ch split-pair)))))
 
 ;; Public API.
 
+(defn ^:export open [path]
+  ;; Eventually, URI.  For now, just a plain path (no file://).
+  (take-pair-as-promise!
+    (go-pair
+      (let [conn (<? (sqlite/<sqlite-connection path))
+            db (<? (db-factory/<db-with-sqlite-connection conn))]
+        (let [c (transact/connection-with-db db)]
+        (clj->js
+          {:conn c
+           :close (fn [] (db/close-db db))
+           :toString (fn [] (str "#<DB " path ">"))
+           :path path}))))))
+
 (defn ^:export q [query & sources]
   (let [query   (cljs.reader/read-string query)]
     (clj->js query)))
diff --git a/src/datomish/js_util.cljs b/src/datomish/js_util.cljs
new file mode 100644
index 00000000..0a4d9006
--- /dev/null
+++ b/src/datomish/js_util.cljs
@@ -0,0 +1,14 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+(ns datomish.js-util)
+
+(defn is-node? []
+  (try
+    (= "[object process]"
+       (.toString (aget js/global "process")))
+    (catch js/ReferenceError e
+      false)
+    (catch js/TypeError e
+      false)))
diff --git a/src/datomish/query/clauses.cljc b/src/datomish/query/clauses.cljc
index 5052b3d0..eb27596d 100644
--- a/src/datomish/query/clauses.cljc
+++ b/src/datomish/query/clauses.cljc
@@ -126,8 +126,8 @@
   "Transform a DataScript Pattern instance into the parts needed
    to build a SQL expression.
 
-  @arg cc A CC instance.
-  @arg pattern The pattern instance.
+  @param cc A CC instance.
+  @param pattern The pattern instance.
   @return an augmented CC"
   [cc pattern]
   (when-not (instance? Pattern pattern)
diff --git a/src/datomish/sqlite.cljc b/src/datomish/sqlite.cljc
index 68f45762..6fcf6639 100644
--- a/src/datomish/sqlite.cljc
+++ b/src/datomish/sqlite.cljc
@@ -101,7 +101,9 @@
 (defn get-user-version [db]
   (go-pair
     (let [row (first (<? (all-rows db ["PRAGMA user_version"])))]
-      (:user_version row))))
+      (or
+        (:user_version row)
+        0))))
 
 (defn set-user-version [db version]
   (execute! db [(str "PRAGMA user_version = " version)]))
diff --git a/test/datomish/db_test.cljc b/test/datomish/db_test.cljc
index 7ba72207..2d972461 100644
--- a/test/datomish/db_test.cljc
+++ b/test/datomish/db_test.cljc
@@ -22,7 +22,7 @@
              [datomish.test-macros :refer [deftest-async deftest-db]]
              [clojure.test :as t :refer [is are deftest testing]]
              [clojure.core.async :refer [go <! >!]]])
-   #?@(:cljs [[datomish.promise-sqlite]
+   #?@(:cljs [[datomish.js-sqlite]
               [datomish.pair-chan]
               [datomish.test-macros :refer-macros [deftest-async deftest-db]]
               [datomish.node-tempfile :refer [tempfile]]
diff --git a/test/datomish/places/import_test.cljc b/test/datomish/places/import_test.cljc
index 4ade271c..af5a5ead 100644
--- a/test/datomish/places/import_test.cljc
+++ b/test/datomish/places/import_test.cljc
@@ -21,7 +21,7 @@
              [datomish.test-macros :refer [deftest-async]]
              [clojure.test :as t :refer [is are deftest testing]]
              [clojure.core.async :refer [go <! >!]]])
-   #?@(:cljs [[datomish.promise-sqlite]
+   #?@(:cljs [[datomish.js-sqlite]
               [datomish.pair-chan]
               [datomish.test-macros :refer-macros [deftest-async]]
               [datomish.node-tempfile :refer [tempfile]]
diff --git a/test/datomish/promise_sqlite_test.cljs b/test/datomish/promise_sqlite_test.cljs
index dde6f23c..ad5d797d 100644
--- a/test/datomish/promise_sqlite_test.cljs
+++ b/test/datomish/promise_sqlite_test.cljs
@@ -14,7 +14,7 @@
    [cljs.test :refer-macros [is are deftest testing async]]
    [datomish.pair-chan]
    [datomish.sqlite :as s]
-   [datomish.promise-sqlite :as ps]))
+   [datomish.js-sqlite :as ps]))
 
 (deftest-async test-all-rows
   (with-tempfile [t (tempfile)]
diff --git a/test/datomish/query_test.cljc b/test/datomish/query_test.cljc
index cd93d777..9564a85f 100644
--- a/test/datomish/query_test.cljc
+++ b/test/datomish/query_test.cljc
@@ -16,7 +16,7 @@
              [datomish.test-macros :refer [deftest-async]]
              [clojure.test :as t :refer [is are deftest testing]]
              [clojure.core.async :refer [go <! >!]]])
-   #?@(:cljs [[datomish.promise-sqlite]
+   #?@(:cljs [[datomish.js-sqlite]
               [datomish.pair-chan]
               [datomish.test-macros :refer-macros [deftest-async]]
               [datomish.node-tempfile :refer [tempfile]]
diff --git a/test/datomish/test/query.cljc b/test/datomish/test/query.cljc
index a34a2f69..7d239daa 100644
--- a/test/datomish/test/query.cljc
+++ b/test/datomish/test/query.cljc
@@ -22,7 +22,7 @@
             [tempfile.core :refer [tempfile with-tempfile]]
             [clojure.test :as t :refer [is are deftest testing]]])
      #?@(:cljs
-           [[datomish.promise-sqlite]
+           [[datomish.js-sqlite]
             [datomish.test-macros :refer-macros [deftest-db]]
             [honeysql.core :as sql :refer-macros [param]]
             [datomish.node-tempfile :refer [tempfile]]
diff --git a/test/datomish/tofinoish_test.cljc b/test/datomish/tofinoish_test.cljc
index 199a4df9..444f0f6b 100644
--- a/test/datomish/tofinoish_test.cljc
+++ b/test/datomish/tofinoish_test.cljc
@@ -17,7 +17,7 @@
              [datomish.test-macros :refer [deftest-async deftest-db]]
              [clojure.test :as t :refer [is are deftest testing]]
              [clojure.core.async :refer [go <! >!]]])
-   #?@(:cljs [[datomish.promise-sqlite]
+   #?@(:cljs [[datomish.js-sqlite]
               [datomish.pair-chan]
               [datomish.test-macros :refer-macros [deftest-async deftest-db]]
               [datomish.node-tempfile :refer [tempfile]]