fix: change target's type in fee estimate map

src/async.rs

@@ -380,7 +380,7 @@ impl AsyncClient {
 
     /// Get an map where the key is the confirmation target (in number of blocks)
     /// and the value is the estimated feerate (in sat/vB).
-    pub async fn get_fee_estimates(&self) -> Result<HashMap<String, f64>, Error> {
+    pub async fn get_fee_estimates(&self) -> Result<HashMap<u16, f64>, Error> {
         let resp = self
             .client
             .get(&format!("{}/fee-estimates", self.url,))
@@ -393,7 +393,7 @@ impl AsyncClient {
                 message: resp.text().await?,
             })
         } else {
-            Ok(resp.json::<HashMap<String, f64>>().await?)
+            Ok(resp.json::<HashMap<u16, f64>>().await?)
         }
     }
 

src/blocking.rs

@@ -343,15 +343,15 @@ impl BlockingClient {
 
     /// Get an map where the key is the confirmation target (in number of blocks)
     /// and the value is the estimated feerate (in sat/vB).
-    pub fn get_fee_estimates(&self) -> Result<HashMap<String, f64>, Error> {
+    pub fn get_fee_estimates(&self) -> Result<HashMap<u16, f64>, Error> {
         let resp = self
             .agent
             .get(&format!("{}/fee-estimates", self.url,))
             .call();
 
         let map = match resp {
             Ok(resp) => {
-                let map: HashMap<String, f64> = resp.into_json()?;
+                let map: HashMap<u16, f64> = resp.into_json()?;
                 Ok(map)
             }
             Err(ureq::Error::Status(code, resp)) => Err(Error::HttpResponse {

src/lib.rs

@@ -80,16 +80,13 @@ pub use r#async::AsyncClient;
 
 /// Get a fee value in sats/vbytes from the estimates
 /// that matches the confirmation target set as parameter.
-pub fn convert_fee_rate(target: usize, estimates: HashMap<String, f64>) -> Result<f32, Error> {
+pub fn convert_fee_rate(target: usize, estimates: HashMap<u16, f64>) -> Result<f32, Error> {
     let fee_val = {
-        let mut pairs = estimates
-            .into_iter()
-            .filter_map(|(k, v)| Some((k.parse::<usize>().ok()?, v)))
-            .collect::<Vec<_>>();
+        let mut pairs = estimates.into_iter().collect::<Vec<(u16, f64)>>();
         pairs.sort_unstable_by_key(|(k, _)| std::cmp::Reverse(*k));
         pairs
             .into_iter()
-            .find(|(k, _)| k <= &target)
+            .find(|(k, _)| *k as usize <= target)
             .map(|(_, v)| v)
             .unwrap_or(1.0)
     };
@@ -332,7 +329,7 @@ mod test {
 
     #[test]
     fn feerate_parsing() {
-        let esplora_fees = serde_json::from_str::<HashMap<String, f64>>(
+        let esplora_fees = serde_json::from_str::<HashMap<u16, f64>>(
             r#"{
   "25": 1.015,
   "5": 2.3280000000000003,