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What is the output of the following code?
var x = 5;
(function () {
console.log(x);
var x = 10;
})();
var x = 5;
(function () {
console.log(x);
var x = 10;
})();
- a)undefined
- b)ReferenceError
- c)5
- d)10
Correct answer is option 'A'. Can you explain this answer?
Verified Answer
What is the output of the following code?var x = 5;(function () { cons...
In this code, the variable "x" is declared and assigned a value of 5. Inside the immediately invoked function expression (IIFE), a new variable "x" is declared using var and assigned a value of 10. Since the scope of the IIFE is separate from the outer scope, the console.log inside the IIFE prints "undefined" because the local "x" overshadows the outer "x".
Most Upvoted Answer
What is the output of the following code?var x = 5;(function () { cons...
Output Explanation:
The output of the code will be undefined.
Code Explanation:
Let's break down the code step by step:
1. The variable x is declared and assigned a value of 5.
2. The code then executes an Immediately Invoked Function Expression (IIFE). An IIFE is a JavaScript function that is immediately executed after it is defined.
3. Inside the IIFE, a local variable x is declared using the var keyword.
4. The code then tries to log the value of x using console.log(x).
5. Since the variable x is declared inside the IIFE, it creates a new local variable x within the function scope. This is known as variable hoisting.
6. However, the local variable x is declared after the console.log(x) statement. So, at the time of execution, the variable x is hoisted to the top of the function scope but without any value assigned to it. Therefore, its value is undefined.
7. Finally, the code logs the value of x, which is undefined.
Key Takeaways:
- In JavaScript, variable declarations are hoisted to the top of their respective scopes. This means that a variable can be used before it is declared, but its value will be undefined.
- In the given code, the local variable x is hoisted to the top of the IIFE, but its value is not assigned until after the console.log(x) statement. So, the value of x remains undefined when it is logged.
The output of the code will be undefined.
Code Explanation:
Let's break down the code step by step:
1. The variable x is declared and assigned a value of 5.
2. The code then executes an Immediately Invoked Function Expression (IIFE). An IIFE is a JavaScript function that is immediately executed after it is defined.
3. Inside the IIFE, a local variable x is declared using the var keyword.
4. The code then tries to log the value of x using console.log(x).
5. Since the variable x is declared inside the IIFE, it creates a new local variable x within the function scope. This is known as variable hoisting.
6. However, the local variable x is declared after the console.log(x) statement. So, at the time of execution, the variable x is hoisted to the top of the function scope but without any value assigned to it. Therefore, its value is undefined.
7. Finally, the code logs the value of x, which is undefined.
Key Takeaways:
- In JavaScript, variable declarations are hoisted to the top of their respective scopes. This means that a variable can be used before it is declared, but its value will be undefined.
- In the given code, the local variable x is hoisted to the top of the IIFE, but its value is not assigned until after the console.log(x) statement. So, the value of x remains undefined when it is logged.
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What is the output of the following code?var x = 5;(function () { console.log(x); var x = 10;})();a)undefinedb)ReferenceErrorc)5d)10Correct answer is option 'A'. Can you explain this answer?
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