JavaScript Interview Question 15

Welcome to our 200 question series of JavaScript interview questions! Whether you are preparing for a job interview or just want to test your knowledge, these questions will help you understand the ins and outs of JavaScript.

Question 15: What is the difference between “==” and “===” in JavaScript?

In JavaScript, “==” is the equality operator, which checks for equality of values. It performs type coercion if the operands are of different types. On the other hand, “===” is the strict equality operator, which checks for equality of values and types without any type coercion.

For example, if we have the following code:

var x = 10;
var y = "10";

console.log(x == y); // true
console.log(x === y); // false

In this example, when using the “==” operator, JavaScript performs type coercion and considers the values to be equal. However, when using the “===” operator, JavaScript checks for strict equality and considers the values to be not equal due to their different types.

It is important to use the appropriate equality operator based on the comparison you want to make. Using “==” may lead to unexpected results if the types of the operands are not taken into account.

So, when writing JavaScript code, be mindful of how you compare values and always consider using the strict equality operator “===” to avoid any potential issues with type coercion.

Conclusion

Understanding the difference between “==” and “===” in JavaScript is crucial to writing reliable and efficient code. By using the correct equality operator, you can ensure that your comparisons are accurate and free from unexpected results.

Thanks for reading our JavaScript interview question 15! Stay tuned for more questions in our series to enhance your JavaScript knowledge.