Visualizing `delete`, `void`, `typeof`, `+`, `-`, `~`, `!`, `await`.
**`delete`** removes a property from an object. **`void`** evaluates an expression and returns `undefined`. **`typeof`** returns a string indicating the type of its operand.
const obj = { a: 1 }; delete obj.a; // obj is {}
void(0); // undefined
typeof "hello"; // "string"
Initial Object:
Result of `delete obj.b`:
Expression `void(10 + 5)`:
Expression `typeof null`:
The unary plus (`+`) attempts to convert its operand to a number. The unary minus (`-`) negates its operand. The bitwise NOT (`~`) inverts all bits. The logical NOT (`!`) inverts the boolean value of its operand.
+"5"; // 5 (number) -"5"; // -5 (number) ~5; // -6 !true; // false
Operand: `let str = "123"`
Result of `+str`:
Result of `-str`:
Operand: `let num = 5`
Result of `~num`:
Operand: `let bool = true`
Result of `!bool`:
The **`await`** operator can only be used inside an `async` function. It pauses the execution of the `async` function until the `Promise` it is waiting for settles (either fulfills or rejects) and then resumes the `async` function's execution.
async function fetchData() {
const data = await fetch('/api/data');
return data.json();
}
Simulating an asynchronous operation that takes 2 seconds.
Status: Ready
Result of `await` expression: