Summary

Strict Comparison in JavaScript

In this lesson from NVK Tech World, we explore the concept of strict comparison in JavaScript, focusing on the triple equals (===) operator and its distinction from the double equals (==) operator.

Key Concepts

Double Equals (==):
- Used for comparing values, but it performs type coercion.
- Example:
  - 2 == 2 results in true.
  - 3 == "3" also results in true despite one being a number and the other a string.
Triple Equals (===):
- Used for strict comparison, meaning it checks both the value and the type of the operands.
- Example:
  - 3 === "3" results in false due to different types (number vs. string).
- Ensures that comparisons between different types (like strings and numbers) do not lead to unexpected results.

Practical Use

When developing software, it's crucial to ensure that you're comparing values of the same type to avoid bugs. The triple equals operator helps maintain type integrity, avoiding mistakes that may arise from JavaScript's type coercion.

Type Checking

You can use the typeof operator to check the type of a variable:

For example:
- typeof "3" results in "string".
- typeof 3 results in "number".

By using strict comparison and type checking, developers can ensure their code behaves as expected.

Video Transcript

Welcome to NVK Tech World. In this lesson we'll be talking about strict comparison in JavaScript. We'll learn about the triple equals operator and its counterpart. As we saw before we can make comparison in JavaScript using the double equal operator in this way. For example if you want to assert that 2 is actually equal to 2 you can use the double equals. So 2 is obviously equal to true therefore the result here which is the boolean value is true. Now if you have 3 and you try to do 3 equal to that's false right? So that out sounds great there is no problem there but then what happens if you try to compare a string that contains a number and an actual number that's where the problem lies. Things get a bit less strict in JavaScript when you do this comparison. For example let's see if the number 3 is actually is equal to the 3 as a string which is not really a number this guy's a string because there are quotes around it. So you're going to get true even though technically this number is not really a string so that's not really a strict comparison in JavaScript. So because of this there is also what's called a triple operator to account for this kind of problem because sometimes usually you want to make sure that you are dealing with the correct types you want to make sure you only have a number when you need a number and you don't want to be mixing numbers with strings in the manner that it might cause a lot of bugs as you're developing your software. So you want to make sure you know exactly what you're working with and am I working with strings am I working in numbers that kind of stuff so that's why we have the triple equals operator. This guy will make a strict comparison it will not tolerate you trying to compare a number inside a string with an actual number. So let's see what we get if we try to compare a string 3 let me put the quotes here with the number 3 you're going to get false because it's a strict operation. This guy here the triple equals will not only check for the value that it thinks the types have in this case they both have value kind of 3 right but the type is different so the triple equals will also make sure to check that the type of each of these operands is the same. Okay also check for the type and let's see the type of each of these guys. Remember we can use that operator called type of to see what the type or something is. Type of this 3 here is a string but the type of the other 3 is a number so they're obviously different types so the triple equals will make sure okay we have kind of the same value but you do not have the same type therefore this is false this is a strict comparison so that's the triple equals okay.