Practice Set 1

Now that we've covered the basics of JavaScript, it's time to put our knowledge to the test. In this practice set, we'll cover a range of topics from variables to objects.

Q1: Adding numbers to strings

Create a variable of type string and try to add a number to it.

Answer

let name = "Harry";
let age = 29;
console.log(name + age); // "Harry29"

In JavaScript, concatenation is the process of combining two or more strings into a single string. When you use the + operator with a string and a number, the number is automatically converted to a string and then concatenated with the original string. We'll cover more about string concatenation in the future.

Q2: Using typeof

Use the typeof keyword to see the data type of the variables in the previous question.

Answer

console.log(typeof name); // "string"
console.log(typeof age); // "number"

When you use the typeof keyword with a variable, it returns a string indicating the data type of that variable. In this case, name is a string, and age is a number.

Q3: Const objects

Create a constant object in JavaScript and then try to change its value to another data type.

Answer

const biodata = { 
    name: "Harry",
    age: 30 
};
biodata = 29; // TypeError: Assignment to constant variable.

When you create a constant in JavaScript, its value cannot be changed. If you try to assign a new value to a constant, you'll get a TypeError.

Q4: Modifying const objects

Try to add a new key to the previous const object.

Answer

const biodata = { 
    name: "Harry", 
    age: 30 
    };
biodata.address = "123 Main St";
console.log(biodata); // { name: "John", age: 30, address: "123 Main St" }

Even though biodata is a constant, we can still modify its properties. This is because the const keyword only prevents us from reassigning the variable to a different value. The object itself is still mutable, which means we can add or change its properties.

Q5: Month dictionary

Create a JavaScript program to make a month dictionary like 1 = January, 2 = February, and so on.

Answer

const months = {
  1: "January",
  2: "February",
  3: "March",
  4: "April",
  5: "May",
  6: "June",
  7: "July",
  8: "August",
  9: "September",
  10: "October",
  11: "November",
  12: "December"
};

Congratulations, you've completed Practice Set 1! If you got everything correct, great job! If not, don't worry - practice makes perfect. Keep practicing and you'll get there.