fix(node): support specifying arrow field types by name (#2704)

The [`FieldLike` type in
arrow.ts](5ec12c9971/nodejs/lancedb/arrow.ts (L71-L78))
can have a `type: string` property, but before this change, actually
trying to create a table that has a schema that specifies field types by
name results in an error:

```
Error: Expected a Type but object was null/undefined
```

This change adds support for mapping some type name strings to arrow
`DataType`s, so that passing `FieldLike`s with a `type: string` property
to `sanitizeField` does not throw an error.

The type names that can be passed are upper/lowercase variations of the
keys of the `constructorsByTypeName` object. This does not support
mapping types that need parameters, such as timestamps which need
timezones.

With this, it is possible to create empty tables from `SchemaLike`
objects without instantiating arrow types, e.g.:

```
    import { SchemaLike } from "../lancedb/arrow"
    // ...
    const schemaLike = {
      fields: [
        {
          name: "id",
          type: "int64",
          nullable: true,
        },
        {
          name: "vector",
          type: "float64",
          nullable: true,
        },
      ],
    // ...
    } satisfies SchemaLike;
    const table = await con.createEmptyTable("test", schemaLike);
 ```

This change also makes `FieldLike.nullable` required since the `sanitizeField` function throws if it is undefined.
This commit is contained in:
Tom LaMarre
2025-10-08 06:40:06 -05:00
committed by GitHub
parent 5ec12c9971
commit 917aabd077
4 changed files with 299 additions and 4 deletions

View File

@@ -10,7 +10,13 @@ import * as arrow16 from "apache-arrow-16";
import * as arrow17 from "apache-arrow-17";
import * as arrow18 from "apache-arrow-18";
import { MatchQuery, PhraseQuery, Table, connect } from "../lancedb";
import {
Connection,
MatchQuery,
PhraseQuery,
Table,
connect,
} from "../lancedb";
import {
Table as ArrowTable,
Field,
@@ -21,6 +27,8 @@ import {
Int64,
List,
Schema,
SchemaLike,
Type,
Uint8,
Utf8,
makeArrowTable,
@@ -2019,3 +2027,52 @@ describe("column name options", () => {
expect(results2.length).toBe(10);
});
});
describe("when creating an empty table", () => {
let con: Connection;
beforeEach(async () => {
const tmpDir = tmp.dirSync({ unsafeCleanup: true });
con = await connect(tmpDir.name);
});
afterEach(() => {
con.close();
});
it("can create an empty table from an arrow Schema", async () => {
const schema = new Schema([
new Field("id", new Int64()),
new Field("vector", new Float64()),
]);
const table = await con.createEmptyTable("test", schema);
const actualSchema = await table.schema();
expect(actualSchema.fields[0].type.typeId).toBe(Type.Int);
expect((actualSchema.fields[0].type as Int64).bitWidth).toBe(64);
expect(actualSchema.fields[1].type.typeId).toBe(Type.Float);
expect((actualSchema.fields[1].type as Float64).precision).toBe(2);
});
it("can create an empty table from schema that specifies field types by name", async () => {
const schemaLike = {
fields: [
{
name: "id",
type: "int64",
nullable: true,
},
{
name: "vector",
type: "float64",
nullable: true,
},
],
metadata: new Map(),
names: ["id", "vector"],
} satisfies SchemaLike;
const table = await con.createEmptyTable("test", schemaLike);
const actualSchema = await table.schema();
expect(actualSchema.fields[0].type.typeId).toBe(Type.Int);
expect((actualSchema.fields[0].type as Int64).bitWidth).toBe(64);
expect(actualSchema.fields[1].type.typeId).toBe(Type.Float);
expect((actualSchema.fields[1].type as Float64).precision).toBe(2);
});
});