make to_json() return string instead of JsValue;

add `to_json_dapp` for `ErgoBox` and `Token`;

Author: greenhat

bindings/ergo-lib-wasm/src/ergo_box.rs

@@ -24,6 +24,7 @@ use wasm_bindgen::prelude::*;
 
 use crate::ast::Constant;
 use crate::ergo_tree::ErgoTree;
+use crate::json::ErgoBoxJsonDapp;
 use crate::token::Tokens;
 use crate::utils::I64;
 use crate::{contract::Contract, transaction::TxId};
@@ -163,12 +164,21 @@ impl ErgoBox {
             .map(Constant::from)
     }
 
-    /// JSON representation
-    pub fn to_json(&self) -> Result<JsValue, JsValue> {
-        JsValue::from_serde(&self.0.clone()).map_err(|e| JsValue::from_str(&format!("{}", e)))
+    /// JSON representation as text (compatible with Ergo Node/Explorer API, numbers are encoded as numbers)
+    pub fn to_json(&self) -> Result<String, JsValue> {
+        serde_json::to_string_pretty(&self.0.clone())
+            .map_err(|e| JsValue::from_str(&format!("{}", e)))
+    }
+
+    /// JSON representation (same as [`Self::to_json`],
+    /// but with box value encoding as string)
+    pub fn to_json_dapp(&self) -> Result<JsValue, JsValue> {
+        let box_dapp: ErgoBoxJsonDapp = self.0.clone().into();
+        JsValue::from_serde(&box_dapp).map_err(|e| JsValue::from_str(&format!("{}", e)))
     }
 
-    /// JSON representation
+    /// parse from JSON
+    /// supports Ergo Node/Explorer API and box values and token amount encoded as strings
     pub fn from_json(json: &str) -> Result<ErgoBox, JsValue> {
         serde_json::from_str(json)
             .map(Self)

bindings/ergo-lib-wasm/src/token.rs

@@ -8,6 +8,7 @@ use ergo_lib::chain::Digest32;
 use wasm_bindgen::prelude::*;
 
 use crate::ergo_box::BoxId;
+use crate::json::TokenJsonDapp;
 use crate::utils::I64;
 
 /// Token id (32 byte digest)
@@ -100,9 +101,17 @@ impl Token {
         TokenAmount(self.0.amount)
     }
 
-    /// JSON representation
-    pub fn to_json(&self) -> Result<JsValue, JsValue> {
-        JsValue::from_serde(&self.0.clone()).map_err(|e| JsValue::from_str(&format!("{}", e)))
+    /// JSON representation as text (compatible with Ergo Node/Explorer API, numbers are encoded as numbers)
+    pub fn to_json(&self) -> Result<String, JsValue> {
+        serde_json::to_string_pretty(&self.0.clone())
+            .map_err(|e| JsValue::from_str(&format!("{}", e)))
+    }
+
+    /// JSON representation (same as [`Self::to_json`],
+    /// but with box value and token amount encoding as strings)
+    pub fn to_json_dapp(&self) -> Result<JsValue, JsValue> {
+        let t_dapp: TokenJsonDapp = self.0.clone().into();
+        JsValue::from_serde(&t_dapp).map_err(|e| JsValue::from_str(&format!("{}", e)))
     }
 }
 

bindings/ergo-lib-wasm/src/transaction.rs

@@ -71,19 +71,21 @@ impl Transaction {
         self.0.id().into()
     }
 
-    /// JSON representation as text (compatible with Ergo Node/Explorer API)
+    /// JSON representation as text (compatible with Ergo Node/Explorer API, numbers are encoded as numbers)
     pub fn to_json(&self) -> Result<String, JsValue> {
         serde_json::to_string_pretty(&self.0.clone())
             .map_err(|e| JsValue::from_str(&format!("{}", e)))
     }
 
-    /// JSON representation (with box value and token amount encoding as strings)
+    /// JSON representation (same as [`Self::to_json`],
+    /// but with box value and token amount encoding as strings)
     pub fn to_json_dapp(&self) -> Result<JsValue, JsValue> {
         let tx_dapp: TransactionJsonDapp = self.0.clone().into();
         JsValue::from_serde(&tx_dapp).map_err(|e| JsValue::from_str(&format!("{}", e)))
     }
 
-    /// JSON representation
+    /// parse from JSON
+    /// supports Ergo Node/Explorer API and box values and token amount encoded as strings
     pub fn from_json(json: &str) -> Result<Transaction, JsValue> {
         serde_json::from_str(json)
             .map(Self)
@@ -144,19 +146,21 @@ impl UnsignedTransaction {
         self.0.output_candidates.clone().into()
     }
 
-    /// JSON representation as text (compatible with Ergo Node/Explorer API)
+    /// JSON representation as text (compatible with Ergo Node/Explorer API, numbers are encoded as numbers)
     pub fn to_json(&self) -> Result<String, JsValue> {
         serde_json::to_string_pretty(&self.0.clone())
             .map_err(|e| JsValue::from_str(&format!("{}", e)))
     }
 
-    /// JSON representation (with box value and token amount encoding as strings)
+    /// JSON representation (same as [`Self::to_json`],
+    /// but with box value and token amount encoding as strings)
     pub fn to_json_dapp(&self) -> Result<JsValue, JsValue> {
         let tx_dapp: UnsignedTransactionJsonDapp = self.0.clone().into();
         JsValue::from_serde(&tx_dapp).map_err(|e| JsValue::from_str(&format!("{}", e)))
     }
 
-    /// JSON representation
+    /// parse from JSON
+    /// supports Ergo Node/Explorer API and box values and token amount encoded as strings
     pub fn from_json(json: &str) -> Result<UnsignedTransaction, JsValue> {
         serde_json::from_str(json)
             .map(Self)

ergo-lib/CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ## [Unreleased] - ReleaseDate
 
 ### Added 
+- WASM `to_json_dapp()` (along `to_json_dapp()`) that encodes the same JSON as `to_json()` but box value and token amount encodes as strings to avoid accuracy loss in JS [#346](https://github.com/ergoplatform/sigma-rust/pull/346);
 - `Coll.slice` [#309](https://github.com/ergoplatform/sigma-rust/pull/309);
 - Byte-wise XOR for byte arrays [#310](https://github.com/ergoplatform/sigma-rust/pull/310);
 - `Constant::from_i64_str_array` and `to_i64_str_array` for `Coll[Long]` encoding [#311](https://github.com/ergoplatform/sigma-rust/pull/311);
@@ -17,14 +18,17 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Better Debug print for EC point [#319](https://github.com/ergoplatform/sigma-rust/pull/319);
 - `Constant::from_ecpoint_bytes` to Wasm API [#324](https://github.com/ergoplatform/sigma-rust/pull/324);
 
-### Changed
-- `SigmaSerializable:sigma_serialize` errors are extended beyond `io::Error` [#328](https://github.com/ergoplatform/sigma-rust/pull/328);
+### Changed(BREAKING)
+- **WASM `to_json()` returns string (instead of `JsValue`) to avoid silent accuracy loss on JS object -> text conversion on JS side [#346](https://github.com/ergoplatform/sigma-rust/pull/346);**
 - `SigmaSerializable:sigma_serialize_bytes` made failible (returns `Result`) [#328](https://github.com/ergoplatform/sigma-rust/pull/328);
 - `ErgoBox::new`, `from_box_candidate` made failible (returns `Result`) [#328](https://github.com/ergoplatform/sigma-rust/pull/328);
 - `ErgoTree::new`, `template_bytes`, `to_base16_bytes` made failible (returns `Result`) [#328](https://github.com/ergoplatform/sigma-rust/pull/328);
 - `Transaction::new`  made failible (returns `Result`) [#328](https://github.com/ergoplatform/sigma-rust/pull/328);
 - WASM `ErgoBox::new`, `byte_to_sign` made failible (returns `Result`) [#328](https://github.com/ergoplatform/sigma-rust/pull/328);
 - WASM `ErgoTree::to_bytes`, `to_base16_bytes` made failible (returns `Result`) [#328](https://github.com/ergoplatform/sigma-rust/pull/328);
+
+### Changed
+- `SigmaSerializable:sigma_serialize` errors are extended beyond `io::Error` [#328](https://github.com/ergoplatform/sigma-rust/pull/328);
 - `ergotree-ir::mir::constant::constant_placeholder` module is public;
 - `ErgoTree::set_constant` is removed in favor of `ErgoTree::with_constant` with an added check for matching constant type[#323](https://github.com/ergoplatform/sigma-rust/pull/323);