@loaders.gl/wkt/dist/hex-wkb-loader.js

Loader and Writer for the WKT (Well Known Text) Format

// loaders.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors
import { WKBLoader } from "./wkb-loader.js";
import { VERSION } from "./lib/utils/version.js";
import { decodeHex } from "./lib/utils/hex-transcoder.js";
/**
 * Worker loader for Hex-encoded WKB (Well-Known Binary)
 */
export const HexWKBLoader = {
    dataType: null,
    batchType: null,
    name: 'Hexadecimal WKB',
    id: 'wkb',
    module: 'wkt',
    version: VERSION,
    worker: true,
    category: 'geometry',
    extensions: ['wkb'],
    mimeTypes: [],
    options: WKBLoader.options,
    text: true,
    testText: isHexWKB,
    // TODO - encoding here seems wasteful - extend hex transcoder?
    parse: async (arrayBuffer) => parseHexWKB(new TextDecoder().decode(arrayBuffer)),
    parseTextSync: parseHexWKB
};
function parseHexWKB(text, options) {
    const uint8Array = decodeHex(text);
    const binaryGeometry = WKBLoader.parseSync?.(uint8Array.buffer, options);
    // @ts-expect-error
    return binaryGeometry;
}
/**
 * Check if string is a valid Well-known binary (WKB) in HEX format
 * https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry
 *
 * @param str input string
 * @returns true if string is a valid WKB in HEX format
 */
export function isHexWKB(string) {
    if (!string) {
        return false;
    }
    // check if the length of the string is even and is at least 10 characters long
    if (string.length < 10 || string.length % 2 !== 0) {
        return false;
    }
    // check if first two characters are 00 or 01
    if (!string.startsWith('00') && !string.startsWith('01')) {
        return false;
    }
    // check if the rest of the string is a valid hex
    return /^[0-9a-fA-F]+$/.test(string.slice(2));
}