Check the difference between JavaScript “==” and “===”

I will explain the difference between “==” and “===”.

“==” and “===” look the same, but there are differences in how they are used.

In this article, we will explain in detail the difference between “==” and “===” and explain when you should use one or the other.

Explanation of “==” and “===”

==is an operator that tests whether values ​​are equal.
===is an operator that strictly tests whether a value and type are equal.

　For example, ==if you compare “1” and “1” using , you truewill get , but ===if you make the same comparison using , falseyou will get . This is because “1” is a number and “1” is a string.

Another example is the result of “0 == false” “0 === false”. ==It true‘s going to be, but ===it’s falsegoing to be. This is falsebecause “0” is a number, and “0” is a boolean value.

Check with sample program

The following sample program confirms the === and ==== behavior.

let num1 = 1;
let num2 = "1";
console.log(num1 == num2); // true
console.log(num1 === num2); // false

let num3 = 0;
let boolean1 = false;
console.log(num3 == boolean1); // true
console.log(num3 === boolean1); // false

let str1 = "hello";
let str2 = "world";
console.log(str1 == str2); // false
console.log(str1 === str2); // false

In the above sample, num1 and num2, num3 and boolean1, str1 and str2 are ==compared ===, and the results are displayed in console.log.

This way ==you can determine whether values ​​are equal, and ===you can see that you can strictly determine whether values ​​and types are equal.

Summary of “==” and “===”

==I will summarize about this ===.

If you want to compare values and types strictly, use ===. On the other hand, === can be used when only values are to be compared.

By using them differently, you can make accurate judgments. Finally, remember that it is always important to be aware of the difference between === and ==== in programming and to make accurate comparisons.

I would prefer to use “====” because I want to compare values and types strictly.