Explain the behavior of the JavaScript ! operator.

In JavaScript, the `!` operator is the logical NOT operator. It is a unary operator, meaning it operates on a single operand. The primary purpose of the `!` operator is to negate the truthiness of its operand.

Here's how the `!` operator works:

- If the operand is truthy, the `!` operator returns `false`.

- If the operand is falsy, the `!` operator returns `true`.

Here's an example:

let isTrue = true;

let isFalse = false;

console.log(!isTrue);  // Outputs: false

console.log(!isFalse); // Outputs: true

In this example, `!isTrue` evaluates to `false` because `isTrue` is initially `true`. Similarly, `!isFalse` evaluates to `true` because `isFalse` is initially `false`.

The `!` operator is often used in conditional statements or expressions to check for the negation of a condition:

let x = 5;

let y = 10;

if (!(x > y)) {

    console.log("x is not greater than y");

} else {

    console.log("x is greater than y");

}

In this example, `!(x > y)` checks if `x` is not greater than `y`. If the condition is true (meaning `x` is not greater than `y`), it executes the block inside the `if` statement.

It's important to note that the `!` operator can also be used multiple times to create double or triple negations, although this can make the code less readable and should be used with caution for clarity:

let isTrue = true;

let doubleNegation = !!isTrue;

console.log(doubleNegation);  // Outputs: true

In this example, `!!isTrue` is a double negation, which is a common technique used to explicitly convert a truthy or falsy value to a boolean.