How to use pouchdb-binary-utils - 10 common examples

function readAsBlobOrBuffer(storedObject, type) {
  // In the browser, we've stored a binary string. This now comes back as a
  // browserified Node-style Buffer (implemented as a typed array),
  // but we want a Blob instead.
  var byteArray = new Uint8Array(storedObject);
  return createBlob([byteArray], {type: type});
}

function readAsBlobOrBuffer(storedObject, type) {
  // In the browser, we've stored a binary string. This now comes back as a
  // browserified Node-style Buffer (implemented as a typed array),
  // but we want a Blob instead.
  var byteArray = new Uint8Array(storedObject);
  return createBlob([byteArray], {type: type});
}

function readAsBlobOrBuffer(storedObject, type) {
  // In the browser, we've stored a binary string. This now comes back as a
  // browserified Node-style Buffer (implemented as a typed array),
  // but we want a Blob instead.
  var byteArray = new Uint8Array(storedObject);
  return pouchdbBinaryUtils.blob([byteArray], {type: type});
}

return new Promise(function (resolve) {
    var blob = createBlob(['']);
    var req = txn.objectStore(DETECT_BLOB_SUPPORT_STORE).put(blob, 'key');

    req.onsuccess = function () {
      var matchedChrome = navigator.userAgent.match(/Chrome\/(\d+)/);
      var matchedEdge = navigator.userAgent.match(/Edge\//);
      // MS Edge pretends to be Chrome 42:
      // https://msdn.microsoft.com/en-us/library/hh869301%28v=vs.85%29.aspx
      resolve(matchedEdge || !matchedChrome ||
        parseInt(matchedChrome[1], 10) >= 43);
    };

    req.onerror = txn.onabort = function (e) {
      // If the transaction aborts now its due to not being able to
      // write to the database, likely due to the disk being full
      e.preventDefault();
      e.stopPropagation();

function readBlobData(body, type, asBlob, callback) {
  if (asBlob) {
    if (!body) {
      callback(createBlob([''], {type: type}));
    } else if (typeof body !== 'string') { // we have blob support
      callback(body);
    } else { // no blob support
      callback(b64StringToBlob(body, type));
    }
  } else { // as base64 string
    if (!body) {
      callback('');
    } else if (typeof body !== 'string') { // we have blob support
      readAsBinaryString(body, function (binary) {
        callback(btoa(binary));
      });
    } else { // no blob support
      callback(body);
    }
  }

function preprocessString(att, blobType, callback) {
  var asBinary = parseBase64(att.data);
  if (asBinary.error) {
    return callback(asBinary.error);
  }

  att.length = asBinary.length;
  if (blobType === 'blob') {
    att.data = binStringToBlobOrBuffer(asBinary, att.content_type);
  } else if (blobType === 'base64') {
    att.data = btoa(asBinary);
  } else { // binary
    att.data = asBinary;
  }
  binaryMd5(asBinary, function (result) {
    att.digest = 'md5-' + result;
    callback();
  });
}

tx.executeSql(sql, [digest], function (tx, result) {
      // websql has a bug where \u0000 causes early truncation in strings
      // and blobs. to work around this, we used to use the hex() function,
      // but that's not performant. after migration 6, we remove \u0000
      // and add it back in afterwards
      var item = result.rows.item(0);
      var data = item.escaped ? unescapeBlob(item.body) :
        parseHexString(item.body, encoding);
      if (opts.binary) {
        res = binStringToBlob(data, type);
      } else {
        res = btoa(data);
      }
      callback(null, res);
    });
  };

stores.binaryStore.get(att.digest, function (err, buffer) {
      var data
      if (err) {
        /* istanbul ignore if */
        if (err.name !== 'NotFoundError') {
          return reject(err)
        } else {
          // empty
          if (!opts.binary) {
            data = ''
          } else {
            data = binStringToBluffer('', type)
          }
        }
      } else { // non-empty
        if (opts.binary) {
          data = readAsBluffer(buffer, type)
        } else {
          data = buffer.toString('base64')
        }
      }
      delete att.stub
      delete att.length
      att.data = data
      resolve()
    })
  })

stores.binaryStore.get(att.digest, function (err, buffer) {
      var data;
      if (err) {
        /* istanbul ignore if */
        if (err.name !== 'NotFoundError') {
          return reject(err);
        } else {
          // empty
          if (!opts.binary) {
            data = '';
          } else {
            data = binStringToBluffer('', type);
          }
        }
      } else { // non-empty
        if (opts.binary) {
          data = readAsBluffer(buffer, type);
        } else {
          data = buffer.toString('base64');
        }
      }
      delete att.stub;
      delete att.length;
      att.data = data;
      resolve();
    });
  });

stores.binaryStore.get(att.digest, function (err, buffer) {
      var data;
      if (err) {
        /* istanbul ignore if */
        if (err.name !== 'NotFoundError') {
          return reject(err);
        } else {
          // empty
          if (!opts.binary) {
            data = '';
          } else {
            data = pouchdbBinaryUtils.binaryStringToBlobOrBuffer('', type);
          }
        }
      } else { // non-empty
        if (opts.binary) {
          data = readAsBlobOrBuffer(buffer, type);
        } else {
          data = buffer.toString('base64');
        }
      }
      delete att.stub;
      delete att.length;
      att.data = data;
      resolve();
    });
  });