file-save.mjs

/**
 * Copyright 2020 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
// @license © 2020 Google LLC. Licensed under the Apache License, Version 2.0.

/**
 * Saves a file to disk using the File System Access API.
 * @type { typeof import("../../index").fileSave }
 */
export default async (
  blob,
  options = {},
  existingHandle = null,
  throwIfExistingHandleNotGood = false
) => {
  options.fileName = options.fileName || 'Untitled';
  const accept = {};
  if (options.mimeTypes) {
    options.mimeTypes.push(blob.type);
    options.mimeTypes.map((mimeType) => {
      accept[mimeType] = options.extensions || [];
    });
  } else {
    accept[blob.type] = options.extensions || [];
  }
  if (existingHandle) {
    try {
      // Check if the file still exists.
      await existingHandle.getFile();
    } catch (err) {
      existingHandle = null;
      if (throwIfExistingHandleNotGood) {
        throw err;
      }
    }
  }
  const handle =
    existingHandle ||
    (await window.showSaveFilePicker({
      suggestedName: options.fileName,
      types: [
        {
          description: options.description || '',
          accept: accept,
        },
      ],
    }));
  const writable = await handle.createWritable();
  await writable.write(blob);
  await writable.close();
  return handle;
};