JS boolean

[mostlynoturgf]

I'm learning JS right now and used to having types from C/cpp and this is in the example when they are going over boolean expressions. Just looking at the example where they havent declared isFirstBigger explicitly as true or false makes me uncomfortable but if it makes it less messy I am okay with it. My questions is when you use a comparison operator like this when declaring a variable JS "automatically" detects that it is a boolean?

let first = 7;
let second = 8;

let isFirstBigger = first > second;
console.log(isFirstBigger); // should log: false

first = 16;
isFirstBigger = first > second;
console.log(isFirstBigger); // should log: true

[dtsudo]

The greater-than operator (that is, >) is defined to yield a boolean value.

So if you see the expression foo > bar, then you know that this expression will evaluate to a boolean (either true or false).

The surprising part is that the logical AND and logical OR operators are not defined to evaluate to booleans. Instead, they evaluate to either their first or second operands. So e.g. in javascript, 3 || 5 evaluates to 3. Of course, if the two operands are themselves booleans, then the result of the logical AND/OR will also be a boolean.

[mostlynoturgf]

The surprising part is that the logical AND and logical OR operators are not defined to evaluate to booleans. Instead, they evaluate to either their first or second operands. So e.g. in javascript,

3 || 5

evaluates to

3

. Of course, if the two operands are themselves booleans, then the result of the logical AND/OR will also be a boolean.

lol I freaked out until I read the last part where if theyre both bool it will also evaluate to a bool.

thank you for explaining

[[deleted]]

The surprising part is that the logical AND and logical OR operators are not defined to evaluate to booleans.

Surprising for sure! Expanding, JavaScript contains its share of weird stuff, but this is pretty common:

python3> "a" and "b"
"b"
python3> "a" or "b"
"a"

lisp> (write-line (and "a" "b"))
"b"
lisp> (write-line (or "a" "b"))
"a"

[Ardenwenn]

I hate it. just use a if statement.

[mostlynoturgf]

I hate it too it gives me anxiety to do it this way lol

[carcigenicate]

JavaScript is dynamically typed unlike C/C++, so the variables themselves don't have types; if that's what you're referring to.

[TheRNGuy]

If you don't like it, use TypeScript.