Implement Statement.columns()

Cargo.toml

@@ -11,7 +11,7 @@ exclude = ["index.node"]
 crate-type = ["cdylib"]
 
 [dependencies]
-libsql = { git = "https://github.com/libsql/libsql/", rev = "3d46e4b328c907b3b4fb229a76bdc9dd335c3334" }
+libsql = { git = "https://github.com/libsql/libsql/", rev = "fa76af21b90f1b40d542e67158289588500d2b00" }
 tokio = { version = "1.29.1", features = [ "rt-multi-thread" ] }
 
 [dependencies.neon]

docs/api.md

@@ -135,7 +135,7 @@ This function enables or disables raw mode. Prepared statements return objects b
 
 ### columns() ⇒ array of objects
 
-This function is currently not supported.
+Returns the columns in the result set returned by this prepared statement.
 
 ### bind([...bindParameters]) ⇒ this
 

index.js

@@ -5,7 +5,20 @@ const { load, currentTarget } = require('@neon-rs/load');
 // Static requires for bundlers.
 if (0) { require('./.targets'); }
 
-const { databaseOpen, databaseOpenWithRpcSync, databaseClose, databaseSync, databaseExec, databasePrepare, statementRaw, statementGet, statementRun, statementRows, rowsNext } = load(__dirname) || require(`@libsql/experimental-${currentTarget()}`);
+const {
+  databaseOpen,
+  databaseOpenWithRpcSync,
+  databaseClose,
+  databaseSync,
+  databaseExec,
+  databasePrepare,
+  statementRaw,
+  statementGet,
+  statementRun,
+  statementRows,
+  statementColumns,
+  rowsNext,
+} = load(__dirname) || require(`@libsql/experimental-${currentTarget()}`);
 
 /**
  * Database represents a connection that can prepare and execute SQL statements.
@@ -202,6 +215,13 @@ class Statement {
        }
        return result;
     }
+
+    /**
+     * Returns the columns in the result set returned by this prepared statement.
+     */
+    columns() {
+        return statementColumns.call(this.stmt);
+    }
 }
 
 module.exports = Database;

integration-tests/tests/basic.test.js

@@ -85,6 +85,35 @@ test("Statement.all() [raw]", async (t) => {
   t.deepEqual(stmt.raw().all(), expected);
 });
 
+test("Statement.columns()", async (t) => {
+  const db = t.context.db;
+
+  const stmt = db.prepare("SELECT * FROM users WHERE id = ?");
+  t.deepEqual(stmt.columns(), [
+    {
+      column: 'id',
+      database: 'main',
+      name: 'id',
+      table: 'users',
+      type: 'INTEGER',
+    },
+    {
+      column: 'name',
+      database: 'main',
+      name: 'name',
+      table: 'users',
+      type: 'TEXT',
+    },
+    {
+      column: 'email',
+      database: 'main',
+      name: 'email',
+      table: 'users',
+      type: 'TEXT',
+    },
+  ]);
+});
+
 test("errors", async (t) => {
   const db = t.context.db;
 

src/lib.rs

@@ -220,6 +220,28 @@ impl Statement {
         };
         Ok(cx.boxed(rows).upcast())
     }
+
+    fn js_columns(mut cx: FunctionContext) -> JsResult<JsValue> {
+        let stmt = cx
+            .this()
+            .downcast_or_throw::<JsBox<Statement>, _>(&mut cx)?;
+        let result = cx.empty_array();
+        for (i, col) in stmt.stmt.columns().iter().enumerate() {
+            let column = cx.empty_object();
+            let column_name = cx.string(col.name());
+            column.set(&mut cx, "column", column_name)?;
+            let column_origin_name = cx.string(col.origin_name().unwrap());
+            column.set(&mut cx, "name", column_origin_name)?;
+            let column_table_name = cx.string(col.table_name().unwrap());
+            column.set(&mut cx, "table", column_table_name)?;
+            let column_database_name = cx.string(col.database_name().unwrap());
+            column.set(&mut cx, "database", column_database_name)?;
+            let column_decl_type = cx.string(col.decl_type().unwrap());
+            column.set(&mut cx, "type", column_decl_type)?;
+            result.set(&mut cx, i as u32, column)?;
+        }
+        Ok(result.upcast())
+    }
 }
 
 struct Rows {
@@ -347,6 +369,7 @@ fn main(mut cx: ModuleContext) -> NeonResult<()> {
     cx.export_function("statementRun", Statement::js_run)?;
     cx.export_function("statementGet", Statement::js_get)?;
     cx.export_function("statementRows", Statement::js_rows)?;
+    cx.export_function("statementColumns", Statement::js_columns)?;
     cx.export_function("rowsNext", Rows::js_next)?;
     Ok(())
 }