move needs an affinity (prepend/append ; left/right)

[Swatinem]

Consider the following example: (https://jsfiddle.net/0eojnd8f/1/)

let s;
s = new MagicString("ABABAB"); // "ABABAB"
s.move(2,3,1); // "AABBAB"
s.move(4,5,1); // "AAABBB"
s.move(3,4,2); // "ABAABB"
s.move(5,6,2); // "ABBAAB"
s = new MagicString("142536"); // "142536"
s.move(2,3,1); // "124536"
s.move(4,5,1); // "123456"
s.move(3,4,2); // "152346"
s.move(5,6,2); // "156234"

I want to group all the As and Bs together, by moving the 2nd/3rd occurence after the first one. However this does not really work as intended.

The other way around, when I move the 1st/2nd before the 3rd one, things work:

s = new MagicString("142536"); // "142536"
s.move(0,1,4); // "425136"
s.move(2,3,4); // "451236"
s.move(1,2,5); // "512346"
s.move(3,4,5); // "123456"

This is a bit weird and unintuitive :-(

[kzc]

@Swatinem It is indeed a shortcoming. A PR supporting movePrependLeft, movePrependRight, moveAppendLeft, moveAppendRight would be welcome.

I imagine these methods could be implemented by making a copy of the substring to be moved, then calling remove and then the corresponding prependLeft, prependRight, appendLeft or appendRight methods. The move method could then be deprecated or removed.

Edit: After thinking about it, I realized that the algorithm outlined above would not work.