We often perform a task based on a condition. For example, if the weather is nice today, then we will go outside. If the alarm clock rings, then we’ll shut it off. If we’re tired, then we’ll go to sleep.
In programming, we can also perform a task based on a condition using an if
statement:
if (true) { console.log('This message will print!'); } // Prints: This message will print!
Notice in the example above, we have an if
statement. The if
statement is composed of:
- The
if
keyword followed by a set of parentheses()
which is followed by a code block, or block statement, indicated by a set of curly braces{}
. - Inside the parentheses
()
, a condition is provided that evaluates totrue
orfalse
. - If the condition evaluates to
true
, the code inside the curly braces{}
runs, or executes. - If the condition evaluates to
false
, the block won’t execute.
Let’s make an if
statement.
Instructions
Using the let
keyword, declare a variable named sale
. Assign the value true
to it.
Now create an if
statement. Provide the if
statement a condition of sale
.
Inside the code block of the if
statement, console.log()
the string 'Time to buy!'
.
Notice that the code inside the if
statement ran, since 'Time to buy!'
was logged to the console.
Below the sale
variable declaration, but before the if
statement, reassign sale
to false
. Run your code and observe what happens, we’ll be changing this behavior in the next exercise.