arquero/dist/types/format/types.d.ts

Query processing and transformation of array-backed data tables.

import { ExtractionOptions, TableBuilderOptions } from '@uwdata/flechette';
import type { Table } from '../table/Table.js';
import type { ColumnType, Select } from '../table/types.js';
/**
 * Options for loading data from files or URLs.
 */
export interface LoadOptions {
    /**
     * Options to pass to the HTTP fetch method when loading a URL.
     */
    fetch?: RequestInit;
    /**
     * Decompression format to apply. If unspecified, the decompression type
     * is inferred from the file extension (.gz or .zz). If no matching extension
     * is found, no decompression is performed.
     */
    decompress?: 'gzip' | 'deflate' | null;
}
/**
 * Column format object.
 */
export interface ValueFormatObject {
    /**
     * If true, format dates in UTC time.
     */
    utc?: boolean;
    /**
     * The number of fractional digits to include when formatting numbers.
     */
    digits?: number;
    /**
     * The maximum string length for formatting nested object or array values.
     */
    maxlen?: number;
}
/**
 * Callback function to format an individual value.
 * @param {*} value The value to format.
 * @return {*} A string-coercible or JSON-compatible formatted value.
 */
export type ValueFormatFunction = (value: any) => any;
/**
 * Value format options.
 */
export type ValueFormatOptions = ValueFormatObject | ValueFormatFunction;
/**
 * Column selection function.
 */
export type ColumnSelectFunction = (table: Table) => string[];
/**
 * Column selection options.
 */
export type ColumnSelectOptions = string[] | ColumnSelectFunction;
/**
 * Column format options. The object keys should be column names.
 * The object values should be formatting functions or objects.
 * If specified, these override any automatically inferred options.
 */
export type ColumnFormatOptions = Record<string, ValueFormatOptions>;
/**
 * Column alignment options. The object keys should be column names.
 * The object values should be aligment strings, one of 'l' (left),
 * 'c' (center), or 'r' (right).
 * If specified, these override any automatically inferred options.
 */
export type ColumnAlignOptions = Record<string, 'l' | 'c' | 'r'>;
/** Arrow input data as bytes or loaded table. */
export type ArrowInput = ArrayBuffer | Uint8Array | ArrowTable;
/** A column in an Apache Arrow table. */
export interface ArrowColumn<T> extends ColumnType<T> {
    type: ArrowDataType;
    nullCount: number;
    toArray(): ColumnType<T>;
}
/** Minimal interface for an Arrow data type. */
export interface ArrowDataType {
    typeId: number;
}
/** A field definition with an Arrow schema. */
export interface ArrowField {
    name: string;
    nullable: boolean;
    type: ArrowDataType;
    metadata?: Map<string, string>;
}
/** An Apache Arrow table schema. */
export interface ArrowSchema {
    version?: number;
    fields: ArrowField[];
    metadata?: Map<string, string>;
}
/**
 * Interface for an Apache Arrow table.
 * Compatible with both Flechette and Arrow-JS table instances.
 */
export interface ArrowTable {
    numRows: number;
    numCols: number;
    schema: ArrowSchema;
    getChild(name: string): ArrowColumn<any>;
    getChildAt(index: number): ArrowColumn<any>;
}
/** Options for Arrow import. */
export interface ArrowOptions extends ExtractionOptions {
    /**
     * An ordered set of columns to import. The input may consist of column name
     * strings, column integer indices, objects with current column names as
     * keys and new column names as values (for renaming), or selection helper
     * functions such as *all*, *not*, or *range*.
     */
    columns?: Select;
}
/** Options for Arrow encoding. */
export interface ArrowFormatOptions extends TableBuilderOptions {
    /**
     * Ordered list of column names to include. If function-valued, the
     * function should accept a dataset as input and return an array of
     * column name strings. If unspecified all columns are included.
     */
    columns?: ColumnSelectOptions;
    /**
     * The maximum number of rows to include (default `Infinity`).
     */
    limit?: number;
    /**
     * The row offset (default `0`) indicating how many initial rows to skip.
     */
    offset?: number;
}
/** Options for Arrow IPC encoding. */
export interface ArrowIPCFormatOptions extends ArrowFormatOptions {
    /**
     * The Arrow IPC byte format to use. One of `'stream'` (default) or `'file'`.
     */
    format?: 'stream' | 'file';
}