Switch to JsValue intrinsics for i64 -> JsValue

As of rustwasm/wasm-bindgen#3049 the builtin conversions no longer use strings, but pass numbers directly, so our custom intrinsic is no longer necessary.

src/bindings.rs

@@ -8,10 +8,4 @@ extern "C" {
 
     #[wasm_bindgen(js_name = BigInt)]
     pub fn bigint_to_i64(x: &BigInt) -> i64;
-
-    #[wasm_bindgen(js_name = BigInt)]
-    pub fn bigint_from_u64(x: u64) -> BigInt;
-
-    #[wasm_bindgen(js_name = BigInt)]
-    pub fn bigint_from_i64(x: i64) -> BigInt;
 }

src/de.rs

@@ -156,7 +156,7 @@ fn convert_pair(pair: JsValue) -> (Deserializer, Deserializer) {
 fn bigint_to_i64(bigint: &BigInt) -> Option<i64> {
     let converted_number = bindings::bigint_to_i64(bigint);
     // Do a round trip check in order to make sure that no information was lost
-    if &bindings::bigint_from_i64(converted_number) == bigint {
+    if *bigint == converted_number {
         Some(converted_number)
     } else {
         None
@@ -166,7 +166,7 @@ fn bigint_to_i64(bigint: &BigInt) -> Option<i64> {
 fn bigint_to_u64(bigint: &BigInt) -> Option<u64> {
     let converted_number = bindings::bigint_to_u64(bigint);
     // Do a round trip check in order to make sure that no information was lost
-    if &bindings::bigint_from_u64(converted_number) == bigint {
+    if *bigint == converted_number {
         Some(converted_number)
     } else {
         None

src/ser.rs

@@ -305,7 +305,7 @@ impl<'s> ser::Serializer for &'s Serializer {
 
     fn serialize_i64(self, v: i64) -> Result {
         if self.serialize_large_number_types_as_bigints {
-            return Ok(bindings::bigint_from_i64(v).into());
+            return Ok(v.into());
         }
 
         // Note: don't try to "simplify" by using `.abs()` as it can overflow,
@@ -325,7 +325,7 @@ impl<'s> ser::Serializer for &'s Serializer {
 
     fn serialize_u64(self, v: u64) -> Result {
         if self.serialize_large_number_types_as_bigints {
-            return Ok(bindings::bigint_from_u64(v).into());
+            return Ok(v.into());
         }
 
         const MAX_SAFE_INTEGER: u64 = 9_007_199_254_740_991;