Merge pull request #14 from zkemail/dimidumo/publicKeyHash_wasm

feat: add public_key_hash wasm bindings

package.json

@@ -8,7 +8,7 @@
     "wasm:postbuild": "node build.js",
     "build": "npm run wasm:build && npm run wasm:postbuild"
   },
-  "version": "0.4.52",
+  "version": "0.4.55",
   "devDependencies": {
     "@types/bun": "latest",
     "prettier": "^3.3.3"

src/wasm.rs

@@ -13,6 +13,8 @@ use crate::{
     AccountSalt, CircuitInputWithDecomposedRegexesAndExternalInputsParams, DecomposedRegex,
     ExternalInput, PaddedEmailAddr, ParsedEmail,
 };
+#[cfg(target_arch = "wasm32")]
+use wasm_bindgen_futures::future_to_promise;
 
 #[wasm_bindgen]
 #[allow(non_snake_case)]
@@ -264,3 +266,48 @@ pub async fn sha256Pad(data: JsValue, max_sha_bytes: usize) -> Promise {
         }
     }
 }
+
+#[wasm_bindgen]
+#[allow(non_snake_case)]
+#[cfg(target_arch = "wasm32")]
+/// Computes the Poseidon hash of a public key.
+///
+/// # Arguments
+///
+/// * `public_key_n` - A `Uint8Array` containing the public key in little endian format.
+///
+/// # Returns
+///
+/// A `Promise` that resolves with the hexadecimal string representation of the hash,
+/// or rejects with an error message.
+pub async fn publicKeyHash(public_key_n: JsValue) -> Promise {
+    use crate::{field_to_hex, public_key_hash};
+    console_error_panic_hook::set_once();
+
+    // We'll wrap the logic in a future so we can use `Promise` and `await`.
+    let future = async move {
+        // Convert JsValue (Uint8Array) to Vec<u8>
+        let mut key_bytes: Vec<u8> = from_value(public_key_n)
+            .map_err(|e| JsValue::from_str(&format!("Failed to convert input: {}", e)))?;
+
+        // Reverse the bytes for little-endian format
+        key_bytes.reverse();
+
+        // Compute the hash
+        let hash = public_key_hash(&key_bytes)
+            .map_err(|e| JsValue::from_str(&format!("Failed to compute hash: {}", e)))?;
+
+        // Convert hash field to hex string
+        let hex_hash = field_to_hex(&hash);
+        to_value(&hex_hash)
+            .map_err(|e| JsValue::from_str(&format!("Failed to serialize result: {}", e)))
+    };
+
+    // Convert the future into a JS Promise
+    future_to_promise(async move {
+        match future.await {
+            Ok(js_value) => Ok(js_value),
+            Err(e) => Err(e),
+        }
+    })
+}

ts_tests/public_key_hash.ts

@@ -0,0 +1,23 @@
+import { expect, test, describe, it } from "bun:test";
+import { publicKeyHash, init } from "../pkg";
+
+const publicKeyHex =
+  "cfb0520e4ad78c4adb0deb5e605162b6469349fc1fde9269b88d596ed9f3735c00c592317c982320874b987bcc38e8556ac544bdee169b66ae8fe639828ff5afb4f199017e3d8e675a077f21cd9e5c526c1866476e7ba74cd7bb16a1c3d93bc7bb1d576aedb4307c6b948d5b8c29f79307788d7a8ebf84585bf53994827c23a5";
+
+// Convert hex string to Uint8Array (no reversal needed)
+function hexToBytes(hex) {
+  return new Uint8Array(hex.match(/.{1,2}/g).map((byte) => parseInt(byte, 16)));
+}
+
+const publicKeyBytes = hexToBytes(publicKeyHex);
+
+// The expected hash result from the Rust test
+const expectedHash = "0x181ab950d973ee53838532ecb1b8b11528f6ea7ab08e2868fb3218464052f953";
+
+describe("publicKeyHash", async () => {
+  await init();
+  it("should correctly hash the public key", async () => {
+    const result = await publicKeyHash(publicKeyBytes);
+    expect(result).toBe(expectedHash);
+  });
+});