3.6 Ternary Operators

The ternary operator — also called the conditional operator — is a concise way to pick between two values based on a condition. Suppose we want to apply a simple business rule: if a customer has more than 100 points they are a "gold" customer, otherwise they are a "silver" customer. Let's express that in JavaScript.

First we declare a variable to track the points:

let points = 110;
let type = points > 100 ? 'gold' : 'silver';
console.log(type); // "gold"

How the ternary operator reads

The syntax follows three parts separated by ? and ::

• A condition that produces a boolean — here points > 100.
• A value used if the condition is true — here 'gold'.
• A value used if the condition is false — here 'silver'.

If we change points to 90, the same expression evaluates to 'silver'. The ternary operator is perfect for short, inline decisions. For more elaborate branching, the regular if / else statement remains clearer. In the next video, we'll dive into logical operators.

Summary

This lesson introduces the ternary (conditional) operator in JavaScript, a compact syntax for assigning values based on conditions. Using a customer loyalty example, it demonstrates how to categorize clients as "gold" (points > 100) or "silver" otherwise. The syntax is `condition ? value_if_true : value_if_false`, providing a more concise alternative to if/else statements for simple assignments.

Key points

• The ternary operator is a conditional expression that evaluates a condition and returns one of two values
• Syntax structure: condition ? value_if_true : value_if_false
• Used for assigning different values to variables based on boolean conditions
• The condition produces a true or false result that determines which value is used
• More concise than if/else for simple conditional assignments
• Example: let type = points > 100 ? 'gold' : 'silver'

FAQ

What is the syntax of the ternary operator?

The syntax is condition ? value_if_true : value_if_false. If the condition evaluates to true, the first value is assigned; if false, the second value is assigned instead.

How is the ternary operator different from an if/else statement?

The ternary operator is a compact expression used specifically for conditional value assignment, while if/else is a control flow statement. The ternary operator is more efficient when you simply need to assign different values based on a condition.

What happens in the example when the points value is changed to 90?

When points equals 90, the condition 'points > 100' evaluates to false, so the variable 'type' is assigned the value 'silver' instead of 'gold'.