JavaScript Switch Case vs If-Else Statement: When to Use Each

In JavaScript, decision-making is a critical part of handling logic. Two commonly used structures for implementing conditional logic are the if-else statement and the switch case. While both serve similar purposes, their use cases, readability, and performance implications differ significantly.

In this guide, we’ll explore how the if-else and switch statements function in JavaScript, examining their syntax, advantages, disadvantages, and key differences. We’ll learn the different coding scenarios where one might be better suited than the other. By the end of this guide, we’ll have a clear understanding of when to use each structure to write cleaner, more efficient, and more readable JavaScript code.

Firstly, let’s discuss what the if-else statement is and how it works in JavaScript.

What is the if-else statement in JavaScript?

The if-else statement is probably the most used conditional statement in JavaScript. It enables our program to make decisions and execute specific blocks of code based on particular conditions. At its core, the if-else statement evaluates a Boolean expression, which results in either true or false. Depending on the outcome, different parts of the code are executed.

The structure begins with an if block, which contains a condition. If that condition evaluates to true, the code within the if block runs. If it evaluates to false, JavaScript moves to the else block and executes the code within it. This means the else block basically acts as a fallback for when the given condition isn’t satisfied.

Here is a flowchart that accurately depicts the flow of the if-else statement:

Next, let’s check out the advantages and disadvantages of using the if-else statement.

Advantages and disadvantages of using the if-else statement

The if-else statement in JavaScript offers several advantages, including:

• Simplicity: Easy to understand and use, especially for beginners.
• Readability: Provides clear and explicit control flow for small sets of conditions.
• Flexibility: Allows complex logic and nesting for multiple decision paths.
• No limit on conditions: Can evaluate a wide range of expressions, including compound and nested conditions.

However, there are some disadvantages as well, such as:

• Scalability issues: Becomes harder to manage and read as the number of conditions grows.
• Error-prone nesting: Deeply nested if-else blocks can lead to confusing and hard-to-maintain code.
• Redundancy: Often requires repeating variable names or conditions, leading to bloated code.
• Difficult debugging: Debugging becomes harder when logic is nested and complex.

With the advantages and disadvantages covered, let’s see the if-else statement in action in the next section.

JavaScript if-else statement example

Let’s first go through the syntax for the if-else statement:

if (condition) {
  // Code to execute if condition is true
} else {
  // Code to execute if condition is false
}

Here, condition refers to the condition to be evaluated.

Next, let’s see an example where we use the if-else statement to see if a given number is greater than or equal to 10:

let num = 12;

if (num >= 10) {
  console.log("The given number is greater than or equal to 10.");
} else {
  console.log("The given number is less than 10.");
}

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In this example, the code within the if statement is executed since the given condition is true, as we can see in the output:

The given number is greater than or equal to 10.

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We can also use an if-else-if ladder to check multiple conditions at once:

if (condition1) {
  // Code to execute if condition1 is true
} else if (condition2) {
  // Code to execute if condition2 is true
} else if (condition3) {
  // Code to execute if condition3 is true
} else {
  // Code to execute if no conditions are met
}

The following example uses the if-else-if ladder to find the grade of a student based on the score obtained:

let score = 85;

if (score >= 90) {
  console.log("Grade: A");
} else if (score >= 80) {
  console.log("Grade: B");
} else if (score >= 70) {
  console.log("Grade: C");
} else {
  console.log("Grade: D");
}

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Since score is greater than or equal to 80, “Grade: B” is printed to the terminal as the output:

Grade: B

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Now that we’re aware of how the if-else statement works, let’s move on to the switch statement, which is another useful conditional statement in JavaScript.

What is a switch statement in JavaScript?

The switch statement or the switch case in JavaScript is a control structure used to perform different actions based on the value of a single expression. It’s particularly useful when we need to compare one variable or expression against a list of possible discrete values, such as strings, numbers, or constants. Instead of writing multiple if-else statements to evaluate the same expression, a switch statement provides a cleaner, more organized approach.

The structure begins with the switch keyword, followed by an expression in parentheses. Then comes a code block containing cases, where each case represents a possible value. The result obtained after evaluating the given expression is compared against these values to find a match. If a match is found, the underlying block of code is executed. The break statement is usually used at the end of each case to prevent the program from continuing to execute the subsequent case blocks, which is known as the fall-through behavior. If no cases match, the default code block runs as a fallback.

Here is a flowchart that demonstrates the flow of the switch statement:

Next, we’ll go through the advantages and disadvantages of using the switch case.

Advantages and disadvantages of using the switch case

There are several advantages of using the switch case in JavaScript, such as:

• Improved readability: The switch case can be more readable and cleaner than multiple if-else blocks, especially when dealing with numerous conditions based on the same variable.
• Faster execution: In some JavaScript engines, switch statements can be optimized for faster execution compared to multiple if-else conditions.
• Structured flow: The structure of a switch case encourages organized branching logic, making it easier to manage and debug.
• Ideal for equality checks: The switch statement is perfect for checking a variable against multiple exact values, avoiding repetitive comparisons.

However, just like if-else, the switch case has some disadvantages as well, including:

• Limited condition types: The switch case only checks for strict equality (===), so it’s unsuitable for conditions involving ranges or complex expressions.
• Potential for errors: Forgetting a break statement can cause unintended fall-through behavior, leading to bugs.
• Harder to maintain with complex logic: For complex or dynamic conditions, switch statements are often harder to maintain and less flexible.
• Verbosity for small cases: Using switch for only two or three conditions can be overkill and less concise than if-else.

Since we’re done exploring the advantages and disadvantages, let’s see how the switch statement works in the next section.

JS switch case example

Firstly, let’s go through the syntax for the switch case:

switch(expression) {
  case value1:
    // Code block to be executed if expression evaluates to value1
  break;

  case value2:
    // Code block to be executed if expression evaluates to value2
  break;

  case value3:
    // Code block to be executed if expression evaluates to value3
  break;

  default:
    // Code block to be executed if no cases are satisfied
}

In the syntax:

• expression: The expression to be evaluated.
• value1, value2, value3: The values that are compared with the value obtained after evaluating expression.

Let’s check out an example that uses the switch statement to determine the access to provide to a user based on its role:

let userRole = "editor";

switch (userRole) {
  case "admin":
    console.log("Access granted: Full access.");
  break;

  case "editor":
    console.log("Access granted: You can edit content.");
  break;

  case "viewer":
    console.log("Access granted: Read-only access.");
  break;

  default:
    console.log("Access denied: Unknown role.");
}

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Since the user role is “Editor”, we get this as the output:

Access granted: You can edit content.

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Let’s see another example where we utilize the switch statement to determine the current day based on the day number:

let day = 3;

switch (day) {
  case 1:
    console.log("Monday");
  break;

  case 2:
    console.log("Tuesday");
  break;

  case 3:
    console.log("Wednesday");
  break;

  case 4:
    console.log("Thursday");
  break;

  case 5:
    console.log("Friday");
  break;

  case 6:
    console.log("Saturday");
  break;

  case 7:
    console.log("Sunday");
  break;

  default:
    console.log("Invalid day number");
}

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Since the day number is 3, the code produces this output:

Wednesday

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We’ve learned quite a bit about the if-else statement and switch case. Next, let’s learn when to use each for optimum usage.

if-else statement vs switch case

Let’s navigate through the scenarios where we should use the if-else statement:

• Situations involving complex conditions with comparison or logical operators
• Cases where multiple variables or expressions are being evaluated
• Range checking or non-equality conditions
• Conditions that are dynamic or calculated at runtime

On the other hand, here are the ideal scenarios for using the switch case:

• Scenarios that involve comparing a single variable against multiple constant values
• Code that benefits from a cleaner, more organized structure than multiple if-else statements
• Conditions where each case represents a distinct, known value
• Implementing state machines or menu selections where each input maps to a specific, well-defined action

If we choose them wisely based on these scenarios, we’ll be able to make our code more readable and organized.

Conclusion

In this tutorial, we explored two of JavaScript’s most widely used conditional structures: the if-else statement and the switch case. We began by understanding how if-else and switch work, their advantages and disadvantages, and how to use them to perform conditional operations in JavaScript. We then looked at the key differences that make them two distinct conditional statements. Finally, we outlined when it makes sense to use one over the other.

By understanding the strengths and limitations of the if-else and switch statements, we’ll be better equipped to write efficient, readable, and maintainable code. Whether we’re building a user interface, processing user input, or managing business logic, using the appropriate conditional statement can make a big difference in the clarity and performance of our JavaScript applications.

If you want to learn more about the if-else and switch statements, check out the Learn JavaScript course on Codecademy.

Frequently Asked Questions

switch (expression) {
  case 1:
    if (condition) {
      // Code to execute if condition is true
    } else {
      // Code to execute if condition is false
    }
  break;
...
}