JavaScript Interview Question – What is Type Coercion?

In JavaScript, type coercion is the process of converting a value from one data type to another. This can happen implicitly or explicitly.

Implicit type coercion occurs when JavaScript automatically converts a value from one data type to another during an operation. For example:

        
            10 + "5" // "105"
        
    

In this example, the number 10 is implicitly coerced into a string when concatenated with the string “5”.

Explicit type coercion, on the other hand, occurs when a developer uses JavaScript’s built-in functions to explicitly convert a value from one data type to another. For example:

        
            var num = "10";
            num = Number(num); // 10
        
    

Here, the string “10” is explicitly coerced into a number using the Number() function.

Type coercion can lead to unexpected behavior and bugs in JavaScript code, so it’s important for developers to be aware of how it works and to use it carefully. Understanding type coercion is also important for acing JavaScript interviews, as it’s a common topic that interviewers like to ask about.

Some common JavaScript interview questions about type coercion include:

• What is type coercion in JavaScript?
• What is the difference between implicit and explicit type coercion?
• Can you give an example of a scenario where type coercion can lead to unexpected results?
• How can you handle type coercion in your JavaScript code to avoid unexpected behavior?

Overall, understanding type coercion is an important aspect of mastering JavaScript, and being able to answer questions about it confidently can help you stand out in job interviews.