Wrapper for the react-native-image-picker and react-native-document-picker. Allow to pick media from gallery on iOS.

AttachmentPicker.ts

import { Platform, ActionSheetIOS } from 'react-native';
import DocumentPicker from 'react-native-document-picker';
import ImagePicker from 'react-native-image-picker';
import RNFS from 'react-native-fs';

type Captions = {
  image: string,
  document: string,
  cancel: string,
  title: string,
};

export class AttachmentPicker {
  private _captions: Captions;

  constructor(captions: Captions = { image: 'Image', document: 'Document', cancel: 'Cancel', title: 'Pick type of media' }) {
    this._captions = captions;
  }

  pick = () => {
    if (Platform.OS === 'ios') {
      return this._pickIOS();
    }

    return new Promise((resolve, reject) => {
      return this._pickDocument(resolve, reject);
    });
  }

  _pickIOS = () => {
    return new Promise((resolve, reject) => {
      const { image, document, cancel, title } = this._captions;
      const options = [image, document, cancel];
      const handlers = [this._pickImage, this._pickDocument, this._pickClosed];
      const cancelButtonIndex = options.indexOf(cancel);

      ActionSheetIOS.showActionSheetWithOptions(
        { options, cancelButtonIndex, title },
        buttonIndex => { handlers[buttonIndex](resolve, reject); }
      );
    });
  }

  _pickImage = (resolve: (payload: any) => void, reject: (payload: any) => void) => {
    ImagePicker.showImagePicker(response => {
      if (response.didCancel) {
        reject(new Error('Action cancelled!'));
      } else {
        const { data: b64Content, type: fileType } = response;
        const b64 = `data:${fileType};base64,${b64Content}`;
        const fileExtension = String(fileType).substr(String(fileType).indexOf('/') + 1);

        resolve({ b64, fileType, fileExtension });
      }
    });
  }

  _pickDocument = async (resolve: (payload: any) => void, reject: (payload: any) => void) => {
    try {
      const result = await DocumentPicker.pick({
        type: [DocumentPicker.types.images, DocumentPicker.types.pdf]
      });

      const fileType = result.type;
      const fileExtension = fileType.substr(fileType.indexOf('/') + 1);
      const realURI = Platform.select({ android: result.uri, ios: decodeURI(result.uri), })
      const b64Content = await RNFS.readFile(realURI, "base64")
      const b64 = `data:${fileType};base64,${b64Content}`;

      resolve({ b64, fileType, fileExtension });
    } catch {
      reject(new Error('Action cancelled!'));
    }
  }

  _pickClosed = (_: any, reject: (payload: any) => void) => {
    reject(new Error('Action cancelled!'));
  }
}