Switch vs if comparison in Javascript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check the value of color using an if statement.

Javascript

if (color [1] 'red') {
  console.log('Color is red');
}

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

A===

B!=

C=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using = instead of === causes assignment instead of comparison.

Using == can cause unexpected type coercion.

Use the strict equality operator === to compare values in JavaScript.

2fill in blank

medium

Complete the switch statement to handle the case when day is 'Monday'.

Javascript

switch(day) {
  case [1]:
    console.log('Start of the work week');
    break;
  default:
    console.log('Another day');
}

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

A'Sunday'

B'Monday'

C'Friday'

D'Saturday'

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around string case labels.

Using the wrong day string.

The case label must match the value you want to check, here 'Monday'.

3fill in blank

hard

Fix the error in the if-else statement to correctly check if score is greater than 50.

Javascript

if (score [1] 50) {
  console.log('Passed');
} else {
  console.log('Failed');
}

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

A==

B<

C=

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using = instead of > causes assignment, not comparison.

Using < checks the wrong condition.

Use > to check if score is greater than 50.

4fill in blank

hard

Fill both blanks to create a switch statement that logs 'Weekend' for Saturday and Sunday.

Javascript

switch(day) {
  case [1]:
  case [2]:
    console.log('Weekend');
    break;
  default:
    console.log('Weekday');
}

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

A'Saturday'

B'Monday'

C'Sunday'

D'Friday'

Attempts:

3 left

💡 Hint

Common Mistakes

Using weekdays instead of weekend days.

Forgetting to include both weekend days.

Use 'Saturday' and 'Sunday' as case labels to group weekend days.

5fill in blank

hard

Fill all three blanks to create an if-else chain that logs the correct message for fruit.

Javascript

if (fruit [1] 'apple') {
  console.log('Apple pie');
} else if (fruit [2] 'banana') {
  console.log('Banana smoothie');
} else {
  console.log([3]);
}

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

A===

C'Unknown fruit'

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using == instead of === can cause unexpected results.

Not using quotes around the string in the else block.

Use strict equality === for comparisons and a string for the default message.

Practice

1.

Which statement best describes when to use switch instead of if in JavaScript?

easy

A. Use switch for complex conditions involving ranges or multiple variables.

B. Use switch only for boolean true/false checks.

C. Use switch when checking one value against many fixed options.

D. Use switch to replace all if statements regardless of condition type.

Solution

1. Step 1: Understand the purpose of switch

   switch is designed to compare one value against many possible fixed cases.

2. Step 2: Compare with if usage

   if is better for complex or varied conditions, like ranges or multiple variables.

3. Final Answer:

   Use switch when checking one value against many fixed options. -> Option C

4. Quick Check:

   switch = fixed value checks [OK]

Hint: Use switch for one value, many options; if for complex checks [OK]

Common Mistakes:

• Using switch for complex range conditions
• Thinking switch works with multiple variables
• Believing switch can replace all if statements

2.

Which of the following is the correct syntax to start a switch statement in JavaScript?

?

easy

A. switch (variable) {

B. switch variable {

C. switch { variable }

D. switch: (variable) {

Solution

1. Step 1: Recall switch syntax

   The correct syntax requires parentheses around the variable: switch (variable) {.

2. Step 2: Identify incorrect options

   Options A, B, and D have syntax errors like missing parentheses or wrong punctuation.

3. Final Answer:

   switch (variable) { -> Option A

4. Quick Check:

   Parentheses needed after switch [OK]

Hint: Remember: switch needs parentheses around the expression [OK]

Common Mistakes:

• Omitting parentheses after switch
• Using curly braces instead of parentheses
• Adding colon after switch keyword

3.

What will be the output of the following code?

const fruit = 'apple';
switch (fruit) {
  case 'banana':
    console.log('Yellow');
    break;
  case 'apple':
    console.log('Red');
    break;
  default:
    console.log('Unknown');
}

medium

A. Yellow

B. Red

C. Unknown

D. No output

Solution

1. Step 1: Check the value of fruit

   The variable fruit is set to 'apple'.

2. Step 2: Match fruit in the switch cases

   The case 'apple' matches, so it prints 'Red' and then breaks.

3. Final Answer:

   Red -> Option B

4. Quick Check:

   fruit='apple' matches case 'apple' [OK]

Hint: Match value exactly in switch cases to find output [OK]

Common Mistakes:

• Forgetting break causes fall-through
• Assuming default runs even if case matches
• Mixing up case values

4.

Find the error in this switch statement and choose the fix:

const day = 3;
switch day {
  case 1:
    console.log('Monday');
    break;
  case 3:
    console.log('Wednesday');
    break;
  default:
    console.log('Other day');
}

medium

A. Add parentheses around day in switch: switch (day) {

B. Replace case 3: with case '3':

C. Remove all break; statements

D. Change default to else

Solution

1. Step 1: Identify syntax error in switch statement

   The switch statement is missing parentheses around the variable: it should be switch (day) {.

2. Step 2: Evaluate other options

   Changing case 3 to string is unnecessary; breaks are needed; default cannot be else.

3. Final Answer:

   Add parentheses around day in switch: switch (day) { -> Option A

4. Quick Check:

   switch needs parentheses [OK]

Hint: Always put parentheses after switch keyword [OK]

Common Mistakes:

• Omitting parentheses after switch
• Confusing case value types
• Removing break causing fall-through

5.

You want to write a program that prints a message based on a score:

• If score is exactly 100, print 'Perfect!'
• If score is between 90 and 99, print 'Great!'
• If score is between 60 and 89, print 'Good'
• Otherwise, print 'Try again'

Which approach is best?

hard

A. Use a switch statement with cases for each range.

B. Use a single if statement with all conditions combined.

C. Use a switch with boolean expressions in cases.

D. Use multiple if and else if statements to check ranges.

Solution

1. Step 1: Analyze the conditions

   The conditions involve ranges, not fixed values, so switch is not suitable.

2. Step 2: Choose the best control structure

   Multiple if and else if statements can check ranges easily and clearly.

3. Final Answer:

   Use multiple if and else if statements to check ranges. -> Option D

4. Quick Check:

   Ranges need if/else if, not switch [OK]

Hint: Use if/else for ranges; switch only for exact matches [OK]

Common Mistakes:

• Trying to use switch for range conditions
• Using switch with boolean expressions (not allowed)
• Combining all conditions in one if without else if