diff --git a/wasm/index.html b/wasm/index.html
index 89c0208..ea59cf9 100644
--- a/wasm/index.html
+++ b/wasm/index.html
@@ -6,11 +6,14 @@ <h1>Dofus optimiser wasm benchmark</h1>
     <p>Energy: <span id="benchmark_energy"></span></p>
 
     <script type="module">
-      import init, { benchmark } from "./pkg/wasm.js";
+      import init, { benchmark, setup } from "./pkg/wasm.js";
 
       async function main() {
         await init();
 
+        // parse items
+        setup();
+
         const t0 = performance.now();
         const energy = benchmark();
         const t1 = performance.now();
diff --git a/wasm/src/benchmark.rs b/wasm/src/benchmark.rs
index 06991da..6967fcf 100644
--- a/wasm/src/benchmark.rs
+++ b/wasm/src/benchmark.rs
@@ -4,9 +4,7 @@ use dofus_set::items::ItemIndex;
 use dofus_set::items::Items;
 use dofus_set::stats::Stat;
 
-pub fn bench() -> f64 {
-    let items = Items::new();
-
+pub fn bench(items: &Items) -> f64 {
     let mut weights = [0.0; 51];
     weights[Stat::Power as usize] = 1.0;
     weights[Stat::Strength as usize] = 1.0;
@@ -29,10 +27,10 @@ pub fn bench() -> f64 {
     let mut initial_set: [Option<_>; 16] = [None; 16];
     initial_set[0] = Some(ItemIndex::new_from_id(2019));
 
-    let optimiser = Optimiser::new(&config, initial_set, &items).unwrap();
+    let optimiser = Optimiser::new(&config, initial_set, items).unwrap();
 
     let final_state = optimiser.optimise().unwrap();
-    let sets = final_state.sets(&items);
+    let sets = final_state.sets(items);
 
     -final_state.energy(&config, &sets)
 }
diff --git a/wasm/src/lib.rs b/wasm/src/lib.rs
index f3beeae..79321e9 100644
--- a/wasm/src/lib.rs
+++ b/wasm/src/lib.rs
@@ -1,8 +1,21 @@
+use std::sync::OnceLock;
+
+use dofus_set::items::Items;
 use wasm_bindgen::prelude::*;
 
 mod benchmark;
 
+fn get_items() -> &'static Items {
+    static ITEMS: OnceLock<Items> = OnceLock::new();
+    ITEMS.get_or_init(Items::new)
+}
+
+#[wasm_bindgen]
+pub fn setup() {
+    get_items();
+}
+
 #[wasm_bindgen]
 pub fn benchmark() -> f64 {
-    benchmark::bench()
+    benchmark::bench(get_items())
 }