faint ivy
In typescript, is it possible to create a new union type from all the possible results of the addition of two union types? The idea would be like this:
type T1 = 0 | 1 | 2;
type T2 = 10 | 20;
type T3 = T1 + T2; // same as type T3 = 10 | 11 | 12 | 20 | 21 | 22
My goal is to create a new Map() with a key that accepts [T1, T2] but since maps don't work with arrays as keys, I need to encode it first by combining the two types into some serialized form.
jaunty magnet
it's possible, but not easily
ts doesn't really do arithmatic on types
it'd probably be easier to just use a string serialization
faint ivy
How do you serialize it while still maintaining the strict typing
Is that possible
Hmm maybe it's more practical to do Map<T1, Map<T2, V>>
Problem with maps in general is you can't assure the compiler that the key will return a value even if you filled up the map with all possible keys
jaunty magnet
you could use a template type
jaunty magnet
Problem with maps in general is you can't assure the compiler that the key will ...
yeah, you could use a record instead
faint ivy
TIL record types exist
Whats the difference between Record<ColorIndex, string> and { [i in ColorIndex]: string }
Or is that just the same thing
fallen rapidsBOT
type Record<K extends keyof any, T> = {
[P in K]: T;
};
export const ColorIndices = [1, -1, 2, -2, 4, -4];
export type Rotation = [ColorIndex, -1 | 1];
export const rotationMatrices: Record<
Rotation[0],
Record<Rotation[1], THREE.Matrix4>>= {
1: {
1: createRotationMatrix([1, 1]),
[-1]: createRotationMatrix([1, -1]),
},
[-1]: {
1: createRotationMatrix([-1, -1]),
[-1]: createRotationMatrix([-1, -1]),
},
2: {
1: createRotationMatrix([2, 1]),
[-1]: createRotationMatrix([2, -1]),
},
[-2]: {
1: createRotationMatrix([-2, -1]),
[-1]: createRotationMatrix([-2, -1]),
},
4: {
1: createRotationMatrix([4, 1]),
[-1]: createRotationMatrix([4, -1]),
},
[-4]: {
1: createRotationMatrix([-4, -1]),
[-1]: createRotationMatrix([-4, -1]),
},
};
This is what I was trying to create but without hardcoding it all
But now that I look at it
Some sort of memoization would probably be better
Using a map
Would be typesafe too as long as I call the createRotationMatrix function if the map.get().get() returns undefined
jaunty magnet
btw if you don't necessarily have that Rotation as an input, you could use template types to flatten the structure as mentoined before
faint ivy
Ohh
Templates seem useful
Might be able to combine that with the memoization strategy I mentioned
Ok yeah they're OP
This code would've been a lot more cluttered without templates
jaunty magnet
Ok yeah they're OP
you should probably have a separator between them
faint ivy
True