Function scope in Javascript - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a variable inside the function scope.

Javascript

function greet() {
  let [1] = 'Hello';
  console.log(greeting);
}
greet();

Drag options to blanks, or click blank then click option'

AsayHello

Bmessage

Cgreet

Dgreeting

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name different from the one logged.

Declaring the variable outside the function.

The variable greeting is declared inside the function using let. This means it is only accessible within the function.

2fill in blank

medium

Complete the code to access a variable declared outside the function.

Javascript

let name = 'Alice';
function sayName() {
  console.log([1]);
}
sayName();

Drag options to blanks, or click blank then click option'

Aname

BName

Cuser

Dusername

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name with wrong capitalization.

Trying to access a variable not declared in scope.

The function can access the variable name declared outside because of JavaScript's scope chain.

3fill in blank

hard

Fix the error in the code by completing the blank with the correct variable name.

Javascript

function test() {
  let score = 10;
  if (true) {
    let score = 20;
    console.log([1]);
  }
  console.log(score);
}
test();

Drag options to blanks, or click blank then click option'

Ascore

BScore

Cscor

Dscores

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect capitalization.

Trying to access a variable that does not exist.

Both score variables are valid but in different scopes. Inside the if-block, score refers to 20, outside it refers to 10.

4fill in blank

hard

Fill both blanks to create a function that returns the sum of two numbers.

Javascript

function add([1], [2]) {
  return a + b;
}
console.log(add(3, 4));

Drag options to blanks, or click blank then click option'

Aa

Bb

Cx

Dy

Attempts:

3 left

💡 Hint

Common Mistakes

Using parameter names different from those in the return statement.

Swapping the order of parameters.

The function parameters must be a and b to match the return statement a + b.

5fill in blank

hard

Fill all three blanks to create a function that updates a variable inside its scope and logs it.

Javascript

function update() {
  let count = 0;
  count [1] 5;
  console.log([2]);
  return [3];
}
update();

Drag options to blanks, or click blank then click option'

A+=

Bcount

D-=

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong operator like -=.

Logging or returning a variable not declared.

The operator += adds 5 to count. Then count is logged and returned.