Equality, inequality

And now we fixed the second version of the analyzer. But the boss heard somewhere about the theory of evaluation with the help of equalities and inequalities. Muffin needs the analyzer to compare the counts of markers of different colors according to the new rules, and the cat quickly executed this logic. And again, the rule “where the paws are fast, bugs are plenty” worked.

To fix this program, we need to go deeper into the comparison operators. To find out whether two values ​​are equal or not, JavaScript uses the ==, !=, === and !== operators.

What does “casts or does not cast values ​​to one type” mean? Let’s look at the examples.

console.log('123' == 123); // Logs true
console.log('123' != 123); // Logs false

The string and the number will be equal to each other. This is the case, because comparing different types with == converts values ​​to a single type. For example, you can get 123 from the '123' string. And the number 123 is equal to the number 123, that is why the comparison returns the true value. For the same reason, the inequality != returns ​false for these values: they can be brought to one type and then they will be equal to each other.

console.log('123' === 123); // Logs false
console.log('123' !== 123); // Logs true

In this case, the result is the opposite. Strict equality === compares the values without converting their types: here, a string and a number. Values of different types are never strictly equal, so the equality comparison returns false. But strict inequality for such values returns true.