From d44dd5b5ae06e7855b829cd17f2a4dbcda0cf915 Mon Sep 17 00:00:00 2001
From: Rushil Kapoor <rushilkapoor@bitgo.com>
Date: Wed, 7 Aug 2024 14:11:59 +0530
Subject: [PATCH] feat: expose `script_pubkey` function within `WrapDescriptor`

BTC-1349
---
 packages/wasm-miniscript/js/index.ts  |  1 +
 packages/wasm-miniscript/src/lib.rs   | 12 +++++++++++-
 packages/wasm-miniscript/test/test.ts | 14 +++++++++++++-
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/packages/wasm-miniscript/js/index.ts b/packages/wasm-miniscript/js/index.ts
index d64782c..fb05739 100644
--- a/packages/wasm-miniscript/js/index.ts
+++ b/packages/wasm-miniscript/js/index.ts
@@ -39,6 +39,7 @@ export type Descriptor = {
   atDerivationIndex(index: number): Descriptor;
   encode(): Uint8Array;
   toAsmString(): string;
+  scriptPubkey(): Uint8Array;
 };
 
 export function isDescriptor(obj: unknown): obj is Descriptor {
diff --git a/packages/wasm-miniscript/src/lib.rs b/packages/wasm-miniscript/src/lib.rs
index 4f457e0..848e88d 100644
--- a/packages/wasm-miniscript/src/lib.rs
+++ b/packages/wasm-miniscript/src/lib.rs
@@ -196,6 +196,16 @@ impl WrapDescriptor {
         }
     }
 
+    #[wasm_bindgen(js_name = scriptPubkey)]
+    pub fn script_pubkey(&self) -> Result<Vec<u8>, JsError> {
+        match &self.0 {
+            WrapDescriptorEnum::Definite(desc) => {
+                Ok(desc.script_pubkey().to_bytes())
+            }
+            _ => Err(JsError::new("Cannot derive from a non-definite descriptor")),
+        }
+    }
+
     fn explicit_script(&self) -> Result<ScriptBuf, JsError> {
         match &self.0 {
             WrapDescriptorEnum::Definite(desc) => {
@@ -250,4 +260,4 @@ pub fn panic_xprv() {
     let dd = d.at_derivation_index(0).unwrap();
 
     let _ = dd.explicit_script().unwrap();
-}
\ No newline at end of file
+}
diff --git a/packages/wasm-miniscript/test/test.ts b/packages/wasm-miniscript/test/test.ts
index 7938056..f611cf0 100644
--- a/packages/wasm-miniscript/test/test.ts
+++ b/packages/wasm-miniscript/test/test.ts
@@ -28,7 +28,7 @@ describe("Descriptor fixtures", function () {
       }
       let expected = fixture.descriptor;
       if (i === 56 || i === 57) {
-        // for reasons I do not really understand, teh `a:and_n` gets converted into `a:and_b` for these
+        // for reasons I do not really understand, the `a:and_n` gets converted into `a:and_b` for these
         expected = expected.replace("and_n", "and_b");
       }
       assert.strictEqual(descriptorString, expected);
@@ -45,6 +45,18 @@ describe("Descriptor fixtures", function () {
         assert.doesNotThrow(() =>
           descriptorFromString(fixture.descriptor, "derivable").atDerivationIndex(0).encode(),
         );
+
+        let descriptorString = fixture.descriptor;
+        if (fixture.checksumRequired === false) {
+          descriptorString = removeChecksum(descriptorString);
+        }
+        const descriptor = descriptorFromString(descriptorString, "derivable");
+        assert.strictEqual(
+          Buffer.from(descriptor.atDerivationIndex(fixture.index ?? 0).scriptPubkey()).toString(
+            "hex",
+          ),
+          fixture.script,
+        );
       }
     });
   });