Create lib/migrations/hits-db.js

lib/migrations/hits-db.js

@@ -0,0 +1,68 @@
+// Initialize a new pageview database. For use with Fauna Schema Migrate:
+// https://github.com/fauna-labs/fauna-schema-migrate#readme
+
+import faunadb from "faunadb";
+const {
+  CreateCollection,
+  CreateIndex,
+  CreateFunction,
+  Query,
+  Collection,
+  Role,
+  Var,
+  Index,
+  Let,
+  Match,
+  Lambda,
+  Get,
+  Create,
+  Update,
+  Add,
+  Select,
+  If,
+  Exists,
+  ToInteger,
+} = faunadb.query;
+
+export default function run() {
+  // initializes the empty database
+  CreateCollection({ name: "hits" });
+
+  // this allows us to quickly pull a post's corresponding row
+  CreateIndex({
+    name: "hits_by_slug",
+    source: Collection("hits"),
+    terms: [
+      {
+        field: ["data", "slug"],
+      },
+    ],
+    unique: false,
+    serialized: true,
+  });
+
+  // a wrapper to get a post's row, add one to it, and return the new tally
+  CreateFunction({
+    name: "increment_hit",
+    body: Query(
+      Lambda(
+        "slug",
+        Let(
+          { match: Match(Index("hits_by_slug"), Var("slug")) },
+          If(
+            Exists(Var("match")),
+            Let(
+              {
+                ref: Select("ref", Get(Var("match"))),
+                hits: ToInteger(Select("hits", Select("data", Get(Var("match"))))),
+              },
+              Update(Var("ref"), { data: { hits: Add(Var("hits"), 1) } })
+            ),
+            Create(Collection("hits"), { data: { slug: Var("slug"), hits: 1 } })
+          )
+        )
+      )
+    ),
+    role: Role("server"),
+  });
+}