What does === mean in js

The strict equality operator ("===") is used in JavaScript to compare the type and value of two values, returning true only if both are exactly equal. Unlike the loose equality operator ("=="), the strict equality operator does not perform type conversions, thus avoiding unexpected results and ensuring a more accurate comparison.

The meaning of the strict equality operator ("===") in JavaScript

In JavaScript, The strict equality operator ("===") is used to compare two values ​​for exact equality, including type and value.

Rules for strict equality comparison:

• Comparison type: The strict equality operator compares the type of the value and the value itself. This means that if the two value types are different, the operator will return false even if the values ​​are the same. For example:

<code class="javascript">console.log(1 === "1"); // false
console.log(true === 1); // false</code>

• Comparing values: If two value types are the same, the operator also compares the actual values. The operator returns true only if the types and values ​​are exactly equal. For example:

<code class="javascript">console.log(1 === 1); // true
console.log("hello" === "hello"); // true</code>

The difference between

<code class="javascript">console.log(1 == "1"); // true (类型转换为数字)
console.log(true == 1); // true (类型转换为数字)</code>

and the loose equality operator ("=="):

There is also a type of loose equality operator in JavaScript ("=="). The loose equality operator allows type conversion, which means it converts the values ​​to the same type before comparing them. Therefore, loose equality operators sometimes produce different results than strict equality operators. For example:

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Best practices for using the strict equality operator: #########It is generally recommended to use the strict equality operator ("===") for comparisons in JavaScript , because it helps avoid unexpected type conversions and ensures more accurate, predictable comparisons. ###

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