I'm working on a program that, before it can do anything else, must be able to convert numbers into other numbers. The program only works with numbers 0 through 11 (representing music notes), so anything greater or less than that must be converted to a number between 0 and 11. But when I run my function, it returns undefined for a lot of numbers.
const TET = 12;
const Notes = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
function NoteConverter(note) {
const doubled = TET * 2;
const tripled = TET * 3;
for (index in Notes) {
if (note == index) {
return index;
} else if (note == index + TET || note == index - TET) {
return index;
} else if (note == index + doubled || note == index - doubled) {
return index;
} else if (note == index + tripled || note == index - tripled) {
return index;
}
}
}
When I run the function using 15 as the number to be converted, I get undefined instead of 3, which it should convert to.
I've been trying to figure out what I'm doing wrong but can't. Any help?
It will concatenate string for index + TET so for example if index is 0 index + TET will be 012 it happens because typeof index is string also it is string because the in keyword also works for objects so it would return key name for object which isn't always a number.
edit: so you either have to go with of notes as suggested in the other answer or make sure that it gets converted to number first ;)
Just replace in with of
const TET = 12;
const Notes = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
function NoteConverter(note) {
const doubled = TET * 2;
const tripled = TET * 3;
for (index of Notes) {
if (note == index) {
return index;
} else if (note == index + TET || note == index - TET) {
return index;
} else if (note == index + doubled || note == index - doubled) {
return index;
} else if (note == index + tripled || note == index - tripled) {
return index;
}
}
}
console.log(NoteConverter(15))