Lecture Notes: The Conditional (Ternary) Operator

Overview

• The conditional operator is another way of writing conditionals, along with if-else statements and switch statements.
• Also known as the ternary operator because it has three parts.

Syntax

• Ternary operator allows writing an if-else statement in one line.
• Basic form:

  condition ? exprIfTrue : exprIfFalse
  

• condition: The condition to evaluate (e.g., age >= 18).
• exprIfTrue: Expression to execute if condition is true (e.g., console.log('I like to drink wine')).
• exprIfFalse: Expression to execute if condition is false (e.g., console.log('I like to drink water')).

Example

1. Defining a variable age:

   const age = 23;
   

2. Using the ternary operator for a simple if-else logic:

   age >= 18 ? console.log('I like to drink wine') : console.log('I like to drink water');
   

3. Result:
   • Outputs: I like to drink wine if age is 23 because the condition is true.
   • Outputs: I like to drink water if age is 15 because the condition is false.

Advantages

• Ternary operator is an operator, which means it produces a value.
• This allows for conditional variable declarations in a concise way:

  const drink = age >= 18 ? 'wine' : 'water';
  console.log(drink);
  // Outputs: 'wine'
  

• More concise and readable compared to traditional if-else blocks:

  let drink;
  if (age >= 18) {
    drink = 'wine';
  } else {
    drink = 'water';
  }
  console.log(drink);
  // Outputs: 'wine'
  

Application in Template Literals

• Ternary operator can be used inside template literals:

  console.log(`I like to drink ${age >= 18 ? 'wine' : 'water'}`);
  // Outputs: 'I like to drink wine'
  

• Conducive for quick decisions and places expecting an expression.

Important Notes

• Ternary operator is not a replacement for if-else statements.
• Ideal for one-liners and simple conditional logic.
• if-else is still needed for executing larger blocks of code based on conditions.

Conclusion

• Ternary operator simplifies code by reducing multi-line if-else statements to single-line expressions.
• Particularly useful within template literals and when variables need to be conditionally declared.

Recommendation

• Make sure to fully understand how the ternary operator works.
• Practice by using it in various coding scenarios to gain familiarity.