arquero/dist/types/format/from-json.d.ts

Query processing and transformation of array-backed data tables.

/**
 * Options for JSON parsing.
 * @typedef {object} JSONParseOptions
 * @property {'columns' | 'rows' | 'ndjson' | null} [type] The format type.
 *  One of `'columns'` (for an object with named column arrays)`, 'rows'` (for
 *  an array for row objects), or `'ndjson'` for [newline-delimited JSON][1]
 *  rows. For `'ndjson'`, each line of text must contain a JSON row object
 *  (with no trailing comma) and string properties must not contain any
 *  newline characters. If no format type is specified, one of `'rows'` or
 *  `'columns'` is inferred from the structure of the parsed JSON.
 *
 *  [1]: https://github.com/ndjson/ndjson-spec
 * @property {boolean} [autoType=true] Flag controlling automatic type
 *  inference for column values. If false, date parsing for input JSON
 *  strings is disabled.
 * @property {Record<string, (value: any) => any>} [parse] Object of column
 *  parsing options. The object keys should be column names. The object values
 *  should be parsing functions that transform values upon input.
 * @property {string[]} [columns] An array of column names to include. JSON
 *  properties missing from this list are not included in the table.
 * @property {number} [skip=0] The number of lines to skip before reading data.
 *  Applicable to newline-delimited (NDJSON) data only.
 * @property {string} [comment] A string used to identify comment lines. Any
 *  lines that start with the comment pattern are skipped. Applicable to
 *   newline-delimited (NDJSON)  data only.
 */
/**
 * Parse JavaScript Object Notation (JSON) data into a table.
 * By default, automatic type inference is performed
 * for input values; string values that match the ISO standard
 * date format are parsed into JavaScript Date objects. To disable this
 * behavior, set the autoType option to false. To perform custom parsing
 * of input column values, use the parse option.
 * @param {string} input The input text or stream.
 * @param {JSONParseOptions} options The JSON parse options.
 * @return {ColumnTable} A new table containing the parsed values.
 */
export function fromJSON(input: string, options?: JSONParseOptions): ColumnTable;
/**
 * Parse a JavaScript Object Notation (JSON) stream into a table.
 * By default, automatic type inference is performed
 * for input values; string values that match the ISO standard
 * date format are parsed into JavaScript Date objects. To disable this
 * behavior, set the autoType option to false. To perform custom parsing
 * of input column values, use the parse option.
 * @param {ReadableStream<string>} input The input text or stream.
 * @param {JSONParseOptions} options The JSON parse options.
 * @return {Promise<ColumnTable>} A Promise to a new table containing the
 *  parsed values.
 */
export function fromJSONStream(input: ReadableStream<string>, options?: JSONParseOptions): Promise<ColumnTable>;
/**
 * Load a JSON file from a URL and return a Promise for an Arquero table.
 * If the loaded JSON is array-valued, an array-of-objects format is assumed
 * and the aq.from method is used to construct the table. Otherwise, a
 * column object format is assumed and aq.fromJSON is applied.
 * @param {string} path The URL or file path to load.
 * @param {import('./types.js').LoadOptions & JSONParseOptions} [options]
 *  JSON parse options.
 * @return {Promise<ColumnTable>} A Promise to an Arquero table.
 * @example aq.loadJSON('data/table.json')
 */
export function loadJSON(path: string, options?: import("./types.js").LoadOptions & JSONParseOptions): Promise<ColumnTable>;
/**
 * Options for JSON parsing.
 */
export type JSONParseOptions = {
    /**
     * The format type.
     * One of `'columns'` (for an object with named column arrays)`, 'rows'` (for
     * an array for row objects), or `'ndjson'` for [newline-delimited JSON][1]
     * rows. For `'ndjson'`, each line of text must contain a JSON row object
     * (with no trailing comma) and string properties must not contain any
     * newline characters. If no format type is specified, one of `'rows'` or
     * `'columns'` is inferred from the structure of the parsed JSON.
     *
     * [1]: https://github.com/ndjson/ndjson-spec
     */
    type?: "columns" | "rows" | "ndjson" | null;
    /**
     * Flag controlling automatic type
     * inference for column values. If false, date parsing for input JSON
     * strings is disabled.
     */
    autoType?: boolean;
    /**
     * Object of column
     * parsing options. The object keys should be column names. The object values
     * should be parsing functions that transform values upon input.
     */
    parse?: Record<string, (value: any) => any>;
    /**
     * An array of column names to include. JSON
     * properties missing from this list are not included in the table.
     */
    columns?: string[];
    /**
     * The number of lines to skip before reading data.
     * Applicable to newline-delimited (NDJSON) data only.
     */
    skip?: number;
    /**
     * A string used to identify comment lines. Any
     * lines that start with the comment pattern are skipped. Applicable to
     * newline-delimited (NDJSON)  data only.
     */
    comment?: string;
};
import { ColumnTable } from '../table/ColumnTable.js';