In JavaScript, automatic type conversion occurs as needed. Comparison operators take two numerical operands. If one of the operands is not of numerical type, it gets converted to a numerical before applying the operation.
Type conversion doesn’t work for all operators.
x < y < z
5 < 10 < 15
Let’s take the values above and see what happens.
(x < y < z) is equivalent to ((x<y)<z).<, they have the same precedence. However, since < has left associativity, the expression is evaluated from left to right. Therefore, 5 < 10 is executed first, and returns true.true < 15. As discussed earlier, type conversion happens, and true is converted to 1.1 < 15, which returns true.15 > 10 > 5
Let’s take the values above and see what happens.
(x > y > z) is equivalent to ((x>y)>z).>, they have the same precedence. However, since > has left associativity, the expression is evaluated from left to right. Therefore, 15 > 10 is executed first and returns true.true > 5. As discussed earlier, type conversion happens and true is converted to 1.1 > 5, which returns false.// Example 1x = 5 < 10console.log("5 < 10 is " + x)console.log(x + " < 15 is " + (x < 15))// Example 2y = 15 > 10console.log("15 > 10 is " + y)console.log(y + " > 5 is " + (y > 5))
These cases can also be solved using logical operators.
Multiple comparison operators are more complex to understand and do not improve the readability of the code. On the other hand, logical operators (AND, OR, NOT) provide more readability and are easy to understand.
Therefore, multiple comparison operators should be avoided by using the AND and OR operators to split the expression.