In JavaScript, equality and strict equality are two ways to compare values for equality, and they are represented by different operators.
-
Equality Operator (
==
):- The equality operator (
==
) compares values for equality after performing type coercion if the operands are of different types. Type coercion is the process of converting the operands to the same type before making the comparison. This can lead to unexpected results, especially when comparing values of different types.
console.log(5 == '5'); // true (values are equal after type coercion) console.log(true == 1); // true (values are equal after type coercion)
In the examples above, the equality operator coerces the types before making the comparison, resulting in
true
for both cases. - The equality operator (
-
Strict Equality Operator (
===
):-
The strict equality operator (
===
) compares both the values and the types of the operands. It does not perform type coercion, and both the value and the type must be the same for the comparison to be true
console.log(5 === '5'); // false (values are not of the same type) console.log(true === 1); // false (values are not of the same type)
In these examples, the strict equality operator returns
false
because it checks both the values and the types without performing any type coercion. -
The strict equality operator (
In summary:
- The equality operator (==) performs type coercion and checks for equality after converting the operands to the same type.
- The strict equality operator (===) does not perform type coercion and checks for equality in both value and type.
It is generally recommended to use the strict equality operator (===) to avoid unexpected behavior that can result from type coercion. Using strict equality helps write more predictable and safer code by ensuring that both the values and types are identical for the comparison to be true.