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feat: add output_schema method to queries (#2717)

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This is a helper utility I need for some of my data loader work. It
makes it easy to see the output schema even when a `select` has been
applied.
This commit is contained in:
Weston Pace
2025-10-14 05:13:28 -07:00
committed by GitHub
parent 03eab0f091
commit 8f8e06a2da
17 changed files with 563 additions and 12 deletions
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15
nodejs/src/util.rs
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@@ -1,7 +1,10 @@
// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: Copyright The LanceDB Authors
use arrow_ipc::writer::FileWriter;
use arrow_schema::Schema;
use lancedb::DistanceType;
use napi::bindgen_prelude::Buffer;
pub fn parse_distance_type(distance_type: impl AsRef<str>) -> napi::Result<DistanceType> {
match distance_type.as_ref().to_lowercase().as_str() {
@@ -15,3 +18,15 @@ pub fn parse_distance_type(distance_type: impl AsRef<str>) -> napi::Result<Dista
))),
}
}
/// Convert an Arrow Schema to an Arrow IPC file buffer
pub fn schema_to_buffer(schema: &Schema) -> napi::Result<Buffer> {
let mut writer = FileWriter::try_new(vec![], schema)
.map_err(|e| napi::Error::from_reason(format!("Failed to create IPC file: {}", e)))?;
writer
.finish()
.map_err(|e| napi::Error::from_reason(format!("Failed to finish IPC file: {}", e)))?;
Ok(Buffer::from(writer.into_inner().map_err(|e| {
napi::Error::from_reason(format!("Failed to get IPC file: {}", e))
})?))
}