Skip to main content

Types

info

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

Arrow DataType classes describe logical column types. You compose schemas, builders, and vectors from these types.

Usage​

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

const schema = new Schema([
  new Field('id', new Int32(), false),
  new Field('name', new Utf8(), true)
]);
import {DataType} from 'apache-arrow';

console.log(DataType.isInt(new Int32()));

Core type families​

Null and boolean​

  • Null
  • Bool

Integer​

  • Int
  • Int8
  • Int16
  • Int32
  • Int64
  • Uint8
  • Uint16
  • Uint32
  • Uint64

Floating point​

  • Float
  • Float16
  • Float32
  • Float64

Binary and text​

  • Binary
  • LargeBinary
  • Utf8
  • LargeUtf8
  • FixedSizeBinary

Temporal​

  • Date_
  • DateDay
  • DateMillisecond
  • Time
  • TimeSecond
  • TimeMillisecond
  • TimeMicrosecond
  • TimeNanosecond
  • Timestamp
  • TimestampSecond
  • TimestampMillisecond
  • TimestampMicrosecond
  • TimestampNanosecond

Decimal​

  • Decimal

Nested​

  • List
  • FixedSizeList
  • Struct
  • Map_
  • Union
  • SparseUnion
  • DenseUnion

Dictionary and intervals​

  • Dictionary
  • Duration
  • DurationSecond
  • DurationMillisecond
  • DurationMicrosecond
  • DurationNanosecond
  • Interval
  • IntervalDayTime
  • IntervalYearMonth

Static type checks​

DataType exports runtime type guards with typed boolean outcomes:

  • DataType.isInt(x: unknown): x is Int
  • DataType.isFloat(x: unknown): x is Float
  • DataType.isUtf8(x: unknown): x is Utf8
  • DataType.isList(x: unknown): x is List
  • DataType.isStruct(x: unknown): x is Struct
  • DataType.isDictionary(x: unknown): x is Dictionary

Migration notes​

Older docs and examples frequently use type-specific vector names (for example Int32Vector). In Apache Arrow JS v21, those are not the primary exported public classes; use:

  • new Int32() / new Utf8() to describe schema-level types
  • makeVector / vectorFromArray to build vectors
  • Schema, Field, and Table for structured data assembly