feat(nodejs): add Table.add progress callback

nodejs/__test__/table.test.ts

@@ -115,6 +115,31 @@ describe.each([arrow15, arrow16, arrow17, arrow18])(
       await expect(table.countRows()).resolves.toBe(1);
     });
 
+    it("should invoke the progress callback", async () => {
+      const events: import("../lancedb").WriteProgress[] = [];
+      await table.add([{ id: 1 }, { id: 2 }, { id: 3 }], {
+        progress: (p) => events.push(p),
+      });
+
+      expect(events.length).toBeGreaterThan(0);
+      const last = events[events.length - 1];
+      expect(last.done).toBe(true);
+      // Earlier callbacks must have done=false.
+      for (const ev of events.slice(0, -1)) {
+        expect(ev.done).toBe(false);
+      }
+      // outputRows reflects the rows added in this call, not table size.
+      expect(last.outputRows).toBe(3);
+      // The input source (an array) reports a row count, so totalRows is set.
+      expect(last.totalRows).toBe(3);
+      // outputRows is monotonic.
+      for (let i = 1; i < events.length; i++) {
+        expect(events[i].outputRows).toBeGreaterThanOrEqual(
+          events[i - 1].outputRows,
+        );
+      }
+    });
+
     it("should let me close the table", async () => {
       expect(table.isOpen()).toBe(true);
       table.close();

nodejs/lancedb/index.ts

@@ -113,6 +113,7 @@ export {
   UpdateOptions,
   OptimizeOptions,
   Version,
+  WriteProgress,
   LsmWriteSpec,
   ColumnAlteration,
 } from "./table";

nodejs/lancedb/table.ts

@@ -46,6 +46,33 @@ import { sanitizeType } from "./sanitize";
 import { IntoSql, toSQL } from "./util";
 export { IndexConfig } from "./native";
 
+/**
+ * Progress snapshot for a write operation, delivered to the `progress`
+ * callback passed to {@link Table.add}.
+ */
+export interface WriteProgress {
+  /** Number of rows written so far. */
+  outputRows: number;
+  /** Number of bytes written so far. */
+  outputBytes: number;
+  /**
+   * Total rows expected, when the input source reports it.
+   *
+   * Always set on the final callback (the one with `done: true`), falling
+   * back to the actual number of rows written when the source could not
+   * report a row count up front.
+   */
+  totalRows?: number;
+  /** Wall-clock seconds since the write started. */
+  elapsedSeconds: number;
+  /** Number of parallel write tasks currently in flight. */
+  activeTasks: number;
+  /** Total number of parallel write tasks (the write parallelism). */
+  totalTasks: number;
+  /** `true` for the final callback; `false` otherwise. */
+  done: boolean;
+}
+
 /**
  * Options for adding data to a table.
  */
@@ -56,6 +83,25 @@ export interface AddDataOptions {
    * If "overwrite" then the new data will replace the existing data in the table.
    */
   mode: "append" | "overwrite";
+
+  /**
+   * Optional callback invoked periodically with write progress.
+   *
+   * The callback is fired once per batch written and once more with
+   * `done: true` when the write completes. Calls are non-blocking — if the
+   * callback is slow, intermediate updates may be dropped to avoid stalling
+   * the write.
+   *
+   * @example
+   * ```ts
+   * await table.add(data, {
+   *   progress: (p) => {
+   *     console.log(`${p.outputRows}/${p.totalRows ?? "?"} rows`);
+   *   },
+   * });
+   * ```
+   */
+  progress: (progress: WriteProgress) => void;
 }
 
 export interface UpdateOptions {
@@ -705,7 +751,7 @@ export class LocalTable extends Table {
     const schema = await this.schema();
 
     const buffer = await fromDataToBuffer(data, undefined, schema);
-    return await this.inner.add(buffer, mode);
+    return await this.inner.add(buffer, mode, options?.progress);
   }
 
   async update(

nodejs/src/table.rs

@@ -9,6 +9,7 @@ use lancedb::table::{
     OptimizeAction, OptimizeOptions, Table as LanceDbTable,
 };
 use napi::bindgen_prelude::*;
+use napi::threadsafe_function::{ThreadsafeFunction, ThreadsafeFunctionCallMode};
 use napi_derive::napi;
 
 use crate::error::NapiErrorExt;
@@ -67,8 +68,16 @@ impl Table {
         schema_to_buffer(&schema)
     }
 
-    #[napi(catch_unwind)]
-    pub async fn add(&self, buf: Buffer, mode: String) -> napi::Result<AddResult> {
+    #[napi(
+        catch_unwind,
+        ts_args_type = "buf: Buffer, mode: string, progressCallback?: (progress: WriteProgressInfo) => void"
+    )]
+    pub async fn add(
+        &self,
+        buf: Buffer,
+        mode: String,
+        progress_callback: Option<ProgressFn>,
+    ) -> napi::Result<AddResult> {
         let batches = ipc_file_to_batches(buf.to_vec())
             .map_err(|e| napi::Error::from_reason(format!("Failed to read IPC file: {}", e)))?;
         let batches = batches
@@ -92,6 +101,17 @@ impl Table {
             return Err(napi::Error::from_reason(format!("Invalid mode: {}", mode)));
         };
 
+        if let Some(tsfn) = progress_callback {
+            op = op.progress(move |p| {
+                // Non-blocking: drop progress events rather than back-pressuring
+                // the write if the JS callback can't keep up.
+                tsfn.call(
+                    WriteProgressInfo::from(p),
+                    ThreadsafeFunctionCallMode::NonBlocking,
+                );
+            });
+        }
+
         let res = op.execute().await.default_error()?;
         Ok(res.into())
     }
@@ -654,6 +674,44 @@ pub struct OptimizeStats {
     pub prune: RemovalStats,
 }
 
+/// Progress snapshot for a write operation, delivered to the JS callback
+/// passed to `Table.add`.
+#[napi(object)]
+#[derive(Clone, Debug)]
+pub struct WriteProgressInfo {
+    /// Number of rows written so far.
+    pub output_rows: i64,
+    /// Number of bytes written so far.
+    pub output_bytes: i64,
+    /// Total rows expected, if the input source reports it.
+    /// Always set on the final callback (where `done` is `true`).
+    pub total_rows: Option<i64>,
+    /// Wall-clock seconds since monitoring started.
+    pub elapsed_seconds: f64,
+    /// Number of parallel write tasks currently in flight.
+    pub active_tasks: i64,
+    /// Total number of parallel write tasks (the write parallelism).
+    pub total_tasks: i64,
+    /// `true` for the final callback; `false` otherwise.
+    pub done: bool,
+}
+
+impl From<&lancedb::table::write_progress::WriteProgress> for WriteProgressInfo {
+    fn from(p: &lancedb::table::write_progress::WriteProgress) -> Self {
+        Self {
+            output_rows: p.output_rows() as i64,
+            output_bytes: p.output_bytes() as i64,
+            total_rows: p.total_rows().map(|n| n as i64),
+            elapsed_seconds: p.elapsed().as_secs_f64(),
+            active_tasks: p.active_tasks() as i64,
+            total_tasks: p.total_tasks() as i64,
+            done: p.done(),
+        }
+    }
+}
+
+type ProgressFn = ThreadsafeFunction<WriteProgressInfo, (), WriteProgressInfo, Status, false>;
+
 ///  A definition of a column alteration. The alteration changes the column at
 /// `path` to have the new name `name`, to be nullable if `nullable` is true,
 /// and to have the data type `data_type`. At least one of `rename` or `nullable`