visgl / loaders.gl / 20382848403

// loaders.gl

// SPDX-License-Identifier: MIT

// Copyright vis.gl contributors

// Based on binary-gltf-utils under MIT license: Copyright (c) 2016-17 Karl Cheng

import {toArrayBuffer} from '@loaders.gl/loader-utils';

/**

 * Parses a data URI into a buffer, as well as retrieving its declared MIME type.

 *

 * @param {string} uri - a data URI (assumed to be valid)

 * @returns {Object} { buffer, mimeType }

 */

export function decodeDataUri(uri: string): {arrayBuffer: ArrayBuffer; mimeType: string} {

  const dataIndex = uri.indexOf(',');

  let buffer;

  let mimeType;

  if (uri.slice(dataIndex - 7, dataIndex) === ';base64') {

    buffer = Buffer.from(uri.slice(dataIndex + 1), 'base64');

    mimeType = uri.slice(5, dataIndex - 7).trim();

  } else {

    buffer = Buffer.from(decodeURIComponent(uri.slice(dataIndex + 1)));

    mimeType = uri.slice(5, dataIndex).trim();

  }

  if (!mimeType) {

    mimeType = 'text/plain;charset=US-ASCII';

  } else if (mimeType.startsWith(';')) {

    mimeType = `text/plain${mimeType}`;

  }

  return {arrayBuffer: toArrayBuffer(buffer), mimeType};

}