6. Quiz Questions
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6. Quiz Questions

6.1. Question 1: Single-valued reference property

Consider the single-valued reference property Committee::chair, which holds a reference to an instance of the class ClubMember. Which of the following JS code fragments represents the preferred implementation of the setter for this property? Select one:

  1. O

    set chair(c) {
  const clubMember_id = (typeof c !==  "object") ? c : c.memberId;
  this._chair = ClubMember.instances[clubMember_id];
}

  2. O

    set chair(c) {
  const clubMember_id = c.memberId;
  this._chair = ClubMember.instances[clubMember_id];
}

  3. O

    set chair(c) {
  const clubMember_id = c;
  this._chair = ClubMember.instances[clubMember_id];
}

  4. O

    set chair(c) {
  this._chair = c;
}

6.2. Question 2: Implementing the CASCADE deletion policy

Making the assumption that books existentially depend on their publishers, implying a CASCADE deletion policy, which of the following Publisher.destroy methods correctly implements the implied deletion policy? Select one:

  1. O

    Publisher.destroy = function (name) {
  for (const key of Object.keys( Book.instances)) {
    const book = Book.instances[key];
    if (book.publisher.name === name) {
      delete book._publisher;
    }
  }
  delete Publisher.instances[name];
};

  2. O

    Publisher.destroy = function (name) {
  for (const key of Object.keys( Book.instances)) {
    const book = Book.instances[key];
    if (book.publisher.name === name) {
      delete Book.instances[key];
    }
  }
  delete Publisher.instances[name];
};

  3. O

    Publisher.destroy = function (name) {
  for (const key of Object.keys( Book.instances)) {
    const book = Book.instances[key];
    if (book.publisher.name === name) {
      book.publisher = undefined;
    }
  }
  delete Publisher.instances[name];
};

6.3. Question 3: JS class model

Consider the following OO class model:

Which is the correct JS class model for the Committee class derived from the above model? Select one:

  1. O

  2. O

  3. O

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