The ternary operator, also known as the conditional operator, is a shorthand way of writing an if-else statement in JavaScript. It takes three operands: a condition, a value to return if the condition is true, and a value to return if the condition is false.

Here's an example:

javascript
 
 
Copy code
let age = 25;
let result = age >= 18 ? "You are an adult" : "You are not an adult";

console.log(result);

In this example, if the age is greater than or equal to 18, the condition age >= 18 evaluates to true, and the ternary operator returns the string "You are an adult". Otherwise, if the condition is false, it returns the string "You are not an adult".

You can read more about the ternary operator in JavaScript here.

A switch statement is a control flow statement in JavaScript that allows you to evaluate an expression and choose different paths of execution based on different cases. It's useful when you have multiple conditions to check and you want to avoid using multiple if-else statements.

Here's an example of how a switch statement works in JavaScript:

javascript
 
 
Copy code
let fruit = "apple";

switch (fruit) {
  case "apple":
    console.log("This is an apple.");
    break;
  case "orange":
    console.log("This is an orange.");
    break;
  case "banana":
    console.log("This is a banana.");
    break;
  default:
    console.log("I'm not sure what fruit this is.");
    break;
}

In this example, the expression being evaluated is fruit. If fruit is "apple", the code inside the first case block will execute and log "This is an apple." If fruit is "orange", the code inside the second case block will execute and log "This is an orange." If fruit is "banana", the code inside the third case block will execute and log "This is a banana." If none of the case values match the expression, the code inside the default block will execute and log "I'm not sure what fruit this is." The break statement is used to exit the switch statement once a case is matched.

Switch statements can be a more concise and easier to read way to handle multiple cases than using a series of if-else statements.

A ternary expression is a conditional expression that allows you to assign a value based on a condition. It is often used as a shorthand for an if-else statement.

Here is an example in JavaScript:

javascript
 
 
Copy code
let age = 18;
let message = (age >= 18) ? "You are an adult" : "You are not an adult";
console.log(message); // Output: You are an adult

In this example, we have a condition age >= 18, and if it is true, the value "You are an adult" is assigned to the message variable, otherwise, the value "You are not an adult" is assigned. The ternary operator (?) separates the condition and the two possible outcomes.

The question mark symbol "?" in React is called the "conditional operator" or "ternary operator". It's a shorthand for an if-else statement. It can be used to render different content based on a condition. Here's an example in JavaScript:

javascript
 
 
Copy code
condition ? expressionIfTrue : expressionIfFalse

If the condition is true, the expressionIfTrue is executed, otherwise, the expressionIfFalse is executed.

Here's an example of how it can be used in a React component to render a different message based on a boolean state:

jsx
 
 
Copy code
function Example({ isLoggedIn }) {
  return (
    <div>
      {isLoggedIn ? <p>Welcome back!</p> : <p>Please log in.</p>}
    </div>
  );
}

In this example, if the isLoggedIn prop is true, it will render "Welcome back!" message, otherwise, it will render "Please log in." message.

To add variables in an if else statement, you can use comparison operators to check the values of the variables. Here's an example in JavaScript:

javascript
 
 
Copy code
let num1 = 5;
let num2 = 10;

if (num1 < num2) {
  console.log("num1 is less than num2");
} else {
  console.log("num1 is greater than or equal to num2");
}

In this example, we define two variables num1 and num2. We then use the less than comparison operator (<) to check if num1 is less than num2. If it is, we print out a message saying so. If it's not, we print out a different message saying that num1 is greater than or equal to num2.

In JavaScript, you can use a conditional (if...else) statement and a loop (for) statement to collect information from several prompts and use the responses to present one final alert.

For example:

js
 
 
Copy code
var i;
var response;
for (i=1; i<=3; i++) {
  response = prompt("Please enter your response " + i);
  //this will prompt the user 3 separate times
}
if (response == "Yes") {
  alert("Thank you!");
  //if the final response is yes, this will be the final alert
} else {
  alert("Sorry, that's not what we were looking for.");
  //if the final response is no, this will be the final alert
}