Practice Review: Using "var", "let", and "const" Statements

Try this exercise to see how well you understood this unit. 

Read this article while opening a Developer Console in your browser. The sequence is ctrl+shift+J on Windows and cmd+option+J on the Mac. Type in each statement and examine the output using the Console tab. 

After reading this article, consider these questions:

  • What is the difference between the "var", "let", and "const" keywords?
  • What is "var" hoisting?
  • Should "dynamic typing" be used in your JavaScript programs?

This exercise does not count towards your grade. It is just for practice!

Initializing a variable

Once you've declared a variable, you can initialize it with a value. You do this by typing the variable name, followed by an equals sign (=), followed by the value you want to give it. For example:

myName = 'Chris';
myAge = 37;

Try going back to the console now and typing in these lines. You should see the value you've assigned to the variable returned in the console to confirm it, in each case. Again, you can return your variable values by typing their name into the console – try these again:

myName;
myAge;

You can declare and initialize a variable at the same time, like this:

let myDog = 'Rover';

This is probably what you'll do most of the time, as it is quicker than doing the two actions on two separate lines.