Add fee_info function

wasm/src/lib.rs

@@ -493,6 +493,21 @@ pub async fn capacity_limit() -> Result<u64, JsError> {
         .await?)
 }
 
+#[wasm_bindgen(js_name = feeInfo)]
+pub async fn fee_info() -> Result<FeeInfo, JsError> {
+    Ok(app_client()
+        .query(|app: InnerApp| {
+            let building = app.bitcoin.checkpoints.building()?;
+            let est_miner_fee =
+                building.fee_rate * app.bitcoin.checkpoints.active_sigset()?.est_witness_vsize();
+            Ok(FeeInfo {
+                bridgeFeeRate: 0.015,
+                minerFeeRate: est_miner_fee,
+            })
+        })
+        .await?)
+}
+
 #[wasm_bindgen(js_name = depositsEnabled)]
 pub async fn deposits_enabled() -> Result<bool, JsError> {
     Ok(app_client()

wasm/src/types.rs

@@ -8,6 +8,12 @@ pub struct DepositAddress {
     pub expiration: u64,
 }
 
+#[wasm_bindgen(getter_with_clone)]
+pub struct FeeInfo {
+    pub minerFeeRate: u64,
+    pub bridgeFeeRate: f32,
+}
+
 #[wasm_bindgen(getter_with_clone)]
 pub struct ValidatorQueryInfo {
     pub jailed: bool,