message: ignore object assign polyfill from coverage
diff: @@ -241,15 +241,19 @@ export const toArray = (arrayLike) => {
  * @return {Object}
  */
  export const assign = (target, ...others) => {
  + /* istanbul ignore else */
  if (isCallable(Object.assign)) {
  return Object.assign(target, ...others);
  }
  + /* istanbul ignore next */
  if (target == null) {
  throw new TypeError('Cannot convert undefined or null to object');
  }
  + /* istanbul ignore next */
  const to = Object(target);
  + /* istanbul ignore next */
  others.forEach(arg => {
  // Skip over if undefined or null
  if (arg != null) {
  @@ -258,7 +262,7 @@ export const assign = (target, ...others) => {
  });
  }
  });
  -
  + /* istanbul ignore next */
  return to;
  };
  