feat(napi): implement value getter for JsNumber

napi/src/js_values/number.rs

@@ -6,6 +6,36 @@ use crate::{sys, Error, Result};
 
 pub struct JsNumber(pub(crate) Value);
 
+impl JsNumber {
+  #[inline]
+  pub fn get_uint32(&self) -> Result<u32> {
+    let mut result = 0;
+    check_status!(unsafe { sys::napi_get_value_uint32(self.0.env, self.0.value, &mut result) })?;
+    Ok(result)
+  }
+
+  #[inline]
+  pub fn get_int32(&self) -> Result<i32> {
+    let mut result = 0;
+    check_status!(unsafe { sys::napi_get_value_int32(self.0.env, self.0.value, &mut result) })?;
+    Ok(result)
+  }
+
+  #[inline]
+  pub fn get_int64(&self) -> Result<i64> {
+    let mut result = 0;
+    check_status!(unsafe { sys::napi_get_value_int64(self.0.env, self.0.value, &mut result) })?;
+    Ok(result)
+  }
+
+  #[inline]
+  pub fn get_double(&self) -> Result<f64> {
+    let mut result = 0_f64;
+    check_status!(unsafe { sys::napi_get_value_double(self.0.env, self.0.value, &mut result) })?;
+    Ok(result)
+  }
+}
+
 impl TryFrom<JsNumber> for u32 {
   type Error = Error;