feat(napi): serialize BigInt to serde::Value (#2659)

crates/napi/src/bindgen_runtime/js_values/bigint.rs

@@ -169,15 +169,19 @@ pub(crate) unsafe fn u128_with_sign_to_napi_value(
   let mut raw_value = ptr::null_mut();
   if cfg!(target_endian = "little") {
     let words = &val as *const u128 as *const u64;
-    check_status!(unsafe {
-      sys::napi_create_bigint_words(env, sign_bit, 2, words, &mut raw_value)
-    })?;
+    check_status!(
+      unsafe { sys::napi_create_bigint_words(env, sign_bit, 2, words, &mut raw_value) },
+      "Failed to create BigInt from u128"
+    )?;
     return Ok(raw_value);
   }
 
   let arr: [u64; 2] = [val as _, (val >> 64) as _];
   let words = &arr as *const u64;
-  check_status!(unsafe { sys::napi_create_bigint_words(env, sign_bit, 2, words, &mut raw_value) })?;
+  check_status!(
+    unsafe { sys::napi_create_bigint_words(env, sign_bit, 2, words, &mut raw_value) },
+    "Failed to create BigInt from u128"
+  )?;
   Ok(raw_value)
 }
 
@@ -242,7 +246,10 @@ impl ToNapiValue for &mut i64n {
 impl ToNapiValue for u64 {
   unsafe fn to_napi_value(env: sys::napi_env, val: Self) -> crate::Result<sys::napi_value> {
     let mut raw_value = ptr::null_mut();
-    check_status!(unsafe { sys::napi_create_bigint_uint64(env, val, &mut raw_value) })?;
+    check_status!(
+      unsafe { sys::napi_create_bigint_uint64(env, val, &mut raw_value) },
+      "Failed to create BigInt from u64"
+    )?;
     Ok(raw_value)
   }
 }

crates/napi/src/bindgen_runtime/js_values/serde.rs

@@ -1,4 +1,5 @@
 use std::marker::PhantomData;
+use std::ptr;
 
 use serde_json::{Map, Number, Value};
 
@@ -51,7 +52,25 @@ impl FromNapiValue for Value {
         }
       }
       #[cfg(feature = "napi6")]
-      ValueType::BigInt => todo!(),
+      ValueType::BigInt => {
+        let n = unsafe { BigInt::from_napi_value(env, napi_val)? };
+        // negative
+        if n.sign_bit {
+          let (v, lossless) = n.get_i64();
+          if lossless {
+            Value::Number(v.into())
+          } else {
+            Value::String(to_string(env, napi_val)?)
+          }
+        } else {
+          let (_, v, lossless) = n.get_u64();
+          if lossless {
+            Value::Number(v.into())
+          } else {
+            Value::String(to_string(env, napi_val)?)
+          }
+        }
+      }
       ValueType::Null => Value::Null,
       ValueType::Function => {
         return Err(Error::new(
@@ -89,6 +108,13 @@ impl FromNapiValue for Value {
   }
 }
 
+fn to_string(env: sys::napi_env, napi_val: sys::napi_value) -> Result<String> {
+  let mut string = ptr::null_mut();
+  check_status!(unsafe { sys::napi_coerce_to_string(env, napi_val, &mut string) })?;
+  let s = unsafe { String::from_napi_value(env, string) }?;
+  Ok(s)
+}
+
 impl ToNapiValue for &Map<String, Value> {
   unsafe fn to_napi_value(env: sys::napi_env, val: Self) -> Result<sys::napi_value> {
     let mut obj = Object::new(&Env::from(env))?;

examples/napi/__tests__/__snapshots__/values.spec.ts.md

@@ -572,6 +572,8 @@ Generated by [AVA](https://avajs.dev).
     ␊
     export declare function generateFunctionAndCallIt(): FunctionData␊
     ␊
+    export declare function getBigintJsonValue(value: bigint): void␊
+    ␊
     export declare function getBtreeMapping(): Record<string, number>␊
     ␊
     export declare function getBuffer(): Buffer␊

examples/napi/__tests__/values.spec.ts

@@ -137,6 +137,7 @@ import {
   testSerdeRoundtrip,
   testSerdeBigNumberPrecision,
   testSerdeBufferBytes,
+  getBigintJsonValue,
   createObjWithProperty,
   receiveObjectOnlyFromJs,
   dateToNumber,
@@ -883,6 +884,14 @@ test('serde-buffer-bytes', (t) => {
   t.is(testSerdeBufferBytes({ code: new ArrayBuffer(0) }), 0n)
 })
 
+test('get bigint json value', (t) => {
+  t.notThrows(() => {
+    getBigintJsonValue(-1n)
+    getBigintJsonValue(1n)
+    getBigintJsonValue(18446744073709551620n)
+  })
+})
+
 test('buffer', (t) => {
   let buf = getBuffer()
   t.is(buf.toString('utf-8'), 'Hello world')

examples/napi/example.wasi-browser.js

@@ -210,6 +210,7 @@ export const f64ArrayToArray = __napiModule.exports.f64ArrayToArray
 export const fibonacci = __napiModule.exports.fibonacci
 export const fnReceivedAliased = __napiModule.exports.fnReceivedAliased
 export const generateFunctionAndCallIt = __napiModule.exports.generateFunctionAndCallIt
+export const getBigintJsonValue = __napiModule.exports.getBigintJsonValue
 export const getBtreeMapping = __napiModule.exports.getBtreeMapping
 export const getBuffer = __napiModule.exports.getBuffer
 export const getBufferSlice = __napiModule.exports.getBufferSlice

examples/napi/example.wasi.cjs

@@ -234,6 +234,7 @@ module.exports.f64ArrayToArray = __napiModule.exports.f64ArrayToArray
 module.exports.fibonacci = __napiModule.exports.fibonacci
 module.exports.fnReceivedAliased = __napiModule.exports.fnReceivedAliased
 module.exports.generateFunctionAndCallIt = __napiModule.exports.generateFunctionAndCallIt
+module.exports.getBigintJsonValue = __napiModule.exports.getBigintJsonValue
 module.exports.getBtreeMapping = __napiModule.exports.getBtreeMapping
 module.exports.getBuffer = __napiModule.exports.getBuffer
 module.exports.getBufferSlice = __napiModule.exports.getBufferSlice

examples/napi/index.cjs

@@ -524,6 +524,7 @@ module.exports.f64ArrayToArray = nativeBinding.f64ArrayToArray
 module.exports.fibonacci = nativeBinding.fibonacci
 module.exports.fnReceivedAliased = nativeBinding.fnReceivedAliased
 module.exports.generateFunctionAndCallIt = nativeBinding.generateFunctionAndCallIt
+module.exports.getBigintJsonValue = nativeBinding.getBigintJsonValue
 module.exports.getBtreeMapping = nativeBinding.getBtreeMapping
 module.exports.getBuffer = nativeBinding.getBuffer
 module.exports.getBufferSlice = nativeBinding.getBufferSlice

examples/napi/index.d.cts

@@ -534,6 +534,8 @@ export interface FunctionData {
 
 export declare function generateFunctionAndCallIt(): FunctionData
 
+export declare function getBigintJsonValue(value: bigint): void
+
 export declare function getBtreeMapping(): Record<string, number>
 
 export declare function getBuffer(): Buffer

examples/napi/src/serde.rs

@@ -69,3 +69,27 @@ impl PackageJsonReader {
     &self.i
   }
 }
+
+#[napi(catch_unwind, ts_args_type = "value: bigint")]
+pub fn get_bigint_json_value(bigint_json_value: Value) {
+  match bigint_json_value {
+    Value::Number(n) => {
+      if let Some(u) = n.as_u64() {
+        assert_eq!(u, 1);
+        return;
+      }
+      if let Some(i) = n.as_i64() {
+        assert_eq!(i, -1);
+        return;
+      }
+      unreachable!("should not happen");
+    }
+    Value::String(s) => {
+      assert_eq!(s, "18446744073709551620");
+      return;
+    }
+    _ => {
+      unreachable!("should not happen");
+    }
+  }
+}