Exercise: Work with Data in JS

For this exercise, write some Javascript code to generate the dataset that you put together in the last exercise

{
  "classes": [{
    "name": "cs5356"
  }],
  "classSessions": [{
    "classId": "cs5356",
    "questions": [{
      "name": "danny",
      "question": "why is the sky blue?",
      "votes": 0
    }]
  }]
}

Try defining the following functions:

• createClass(className)
• createClassSession(className)
• askQuestion(userName, question, classSession)
• getClasses(userName)
• getClassSession(sessionCode)

View the example from class

let database = {
  classes: [],
  classSessions: [],
};

const getRandomNumber = () => {
  return `${Math.floor(Math.random() * 900000) + 100000}`;
};

export const createClass = className => {
  database.classes.push({
    className: className,
  });
};

export const getClasses = () => {
  return database.classes;
};

export const createClassSession = className => {
  // find the class with the class name
  const classInfo = database.classes.find(classInfo => {
    return classInfo.className === className;
  });

  database.classSessions.push({
    className: className,
    id: getRandomNumber(),
    questions: [],
  });
};

export const getClassSessions = className => {
  // find the class with the class name
  const classSession = database.classSessions.filter(classSession => {
    return classSession.className === className;
  });
  return classSession;
};

export const askQuestion = (name, question, classSessionId) => {
  const classSession = database.classSessions.find(
    classSession => classSession.id === classSessionId
  );
  classSession.questions.push({
    name: name,
    question: question,
    timestamp: Date.now(),
  });
};

export const getQuestions = classSession => {
  // find the question for a class session
  return database.questions.filter(question => {
    return question.classSession === classSession;
  });
};

export const clear = () => {
  database = {
    classes: [],
    classSessions: [],
  };
};

In the next section, we'll work on making these functions available over the internet.