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StructVector

info

This page is aligned to Apache Arrow JS v21.x (apache-arrow).

StructVector is no longer exposed as a separate public class in Apache Arrow JS v21. Structured values are represented by Vector<Struct<...>>, and row-level access is delivered through StructRow/StructRowProxy.

Usage​

import {vectorFromArray, Struct, Field, Int32, Utf8} from 'apache-arrow';

const rows = vectorFromArray(
  [
    {id: 1, name: 'Alice'},
    {id: 2, name: 'Bob'}
  ],
  new Struct([new Field('id', new Int32()), new Field('name', new Utf8())])
);

console.log(rows.get(0)?.name);

Accessing structured data​

Use get / at / set on the vector to access row objects.

  • get(index) / at(index) returns a row proxy.
  • getChild(name | index) returns nested child vectors.
  • toArray() returns row proxies for each row.
import {vectorFromArray, Struct, Field, Int32, Utf8} from 'apache-arrow';

const rows = vectorFromArray(
  [
    {id: 1, name: 'Alice'},
    {id: 2, name: 'Bob'}
  ],
  new Struct([new Field('id', new Int32()), new Field('name', new Utf8())])
);

const first = rows.get(0);
console.log(first?.name);