If...Else Statements

If…else statements

If…else statements allow you to execute certain pieces of code based on a condition, or set of conditions, being met.

if (/* this expression is true */) {
  // run this code
} else {
  // run this code
}

This is extremely helpful because it allows you to choose which piece of code you want to run based on the result of an expression. For example,

var a = 1;
var b = 2;

if (a > b) {
  console.log("a is greater than b");
} else {
  console.log("a is less than or equal to b");
}

Prints: "a is less than or equal to b"

A couple of important things to notice about if...else statements.

The value inside the if statement is always converted to true or false. Depending on the value, the code inside the if statement is run or the code inside the else statement is run, but not both. The code inside the if and else statements are surrounded by curly braces {...} to separate the conditions and indicate which code should be run.

TIP: When coding, sometimes you may only want to use an if statement. However, if you try to use only an else statement, then you will receive the error SyntaxError: Unexpected token else. You’ll see this error because else statements need an if statement in order to work. You can’t have an else statement without first having an if statement.

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