feat(js): add helper function to create Arrow Table with schema (#838)

Support to make Apache Arrow Table from an array of javascript Records,
with optionally provided Schema.

node/src/test/arrow.test.ts

@@ -0,0 +1,108 @@
+// Copyright 2024 Lance Developers.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { describe } from 'mocha'
+import { assert } from 'chai'
+
+import { fromTableToBuffer, makeArrowTable } from '../arrow'
+import {
+  Field,
+  FixedSizeList,
+  Float16,
+  Float32,
+  Int32,
+  tableFromIPC,
+  Schema,
+  Float64
+} from 'apache-arrow'
+
+describe('Apache Arrow tables', function () {
+  it('customized schema', async function () {
+    const schema = new Schema([
+      new Field('a', new Int32()),
+      new Field('b', new Float32()),
+      new Field('c', new FixedSizeList(3, new Field('item', new Float16())))
+    ])
+    const table = makeArrowTable(
+      [
+        { a: 1, b: 2, c: [1, 2, 3] },
+        { a: 4, b: 5, c: [4, 5, 6] },
+        { a: 7, b: 8, c: [7, 8, 9] }
+      ],
+      { schema }
+    )
+
+    const buf = await fromTableToBuffer(table)
+    assert.isAbove(buf.byteLength, 0)
+
+    const actual = tableFromIPC(buf)
+    assert.equal(actual.numRows, 3)
+    const actualSchema = actual.schema
+    assert.deepEqual(actualSchema, schema)
+  })
+
+  it('default vector column', async function () {
+    const schema = new Schema([
+      new Field('a', new Float64()),
+      new Field('b', new Float64()),
+      new Field(
+        'vector',
+        new FixedSizeList(3, new Field('item', new Float32()))
+      )
+    ])
+    const table = makeArrowTable([
+      { a: 1, b: 2, vector: [1, 2, 3] },
+      { a: 4, b: 5, vector: [4, 5, 6] },
+      { a: 7, b: 8, vector: [7, 8, 9] }
+    ])
+
+    const buf = await fromTableToBuffer(table)
+    assert.isAbove(buf.byteLength, 0)
+
+    const actual = tableFromIPC(buf)
+    assert.equal(actual.numRows, 3)
+    const actualSchema = actual.schema
+    assert.deepEqual(actualSchema, schema)
+  })
+
+  it('2 vector columns', async function () {
+    const schema = new Schema([
+      new Field('a', new Float64()),
+      new Field('b', new Float64()),
+      new Field('vec1', new FixedSizeList(3, new Field('item', new Float16()))),
+      new Field('vec2', new FixedSizeList(3, new Field('item', new Float16())))
+    ])
+    const table = makeArrowTable(
+      [
+        { a: 1, b: 2, vec1: [1, 2, 3], vec2: [2, 4, 6] },
+        { a: 4, b: 5, vec1: [4, 5, 6], vec2: [8, 10, 12] },
+        { a: 7, b: 8, vec1: [7, 8, 9], vec2: [14, 16, 18] }
+      ],
+      {
+        vectorColumns: {
+          vec1: { type: new Float16() },
+          vec2: { type: new Float16() }
+        }
+      }
+    )
+
+    const buf = await fromTableToBuffer(table)
+    assert.isAbove(buf.byteLength, 0)
+
+    const actual = tableFromIPC(buf)
+    assert.equal(actual.numRows, 3)
+    const actualSchema = actual.schema
+    assert.deepEqual(actualSchema, schema)
+  })
+})