The difference between == and === in js

The difference between == and === in JavaScript: == performs a loose equality comparison, forcing the values ​​to be converted to the same type before comparison; === performs a strict equality comparison, comparing not only values ​​but also types, different Type values ​​are always unequal.

The difference between == and === in JavaScript

In JavaScript, == and === are two different equality operators that are used to compare two values ​​for equality.

#== (Loose Equality) The

== operator performs a loose equality comparison, which means it will Try casting two values ​​to the same type and then compare their values. Here are some examples of the behavior of the == operator:

<code>1 == "1" // true
0 == false // true
[] == "" // true</code>

=== (strict equality)

# The ##=== operator performs a strict equality comparison, which means that it not only compares the values ​​of two values, but also their types. The === operator will always return false if the two values ​​are not of the same type. Here are some examples of how the === operators behave:

<code>1 === "1" // false
0 === false // false
[] === "" // false</code>

Usage Guidelines

In general, it is recommended to use strict in JavaScript code Equality operator

===. This is because the behavior of the == operator can lead to unexpected results, especially when different types of values ​​are involved.

However, in some cases it is appropriate to use the loose equality operator

==. For example, when you just want to compare the textual representation of two values ​​and don't care about their types.

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