"explode" measure by measure

Hi! I'm not sure I understand what you are doing here. Why are you going measure by measure instead of just selecting the whole passage? Is the idea that you don't want single notes to get copied to multiple staves? Can you explain more about that use case? I am not understanding how that would ever come up, but if there is something we are missing, we could conceivably enhance the tool to handle that special case better.

You can control how many staves a line gets exploded onto by selecting the staves you want affected. If you select just one staff, it explodes each chord across however many staves are needed. If you select multiple staves, it explodes only across those staves. Maybe somehow this can help.

Meanwhile, in a plugin, you can involve any command by its internal name using the "cmd" function, something like that. Sorry, I know more about the internals than about the plugin interface.

You can invoke the "explode" command by calling cmd("explode"); in your plugin. However you would need to establish a selection on a measure first. The best way to do so will be available in MuseScore 3.5 (which is now in a release candidate stage) which would add selectRange() method to Selection object. However a similar thing can be achieved in earlier versions with something like this:

// Remember current track number (to restore a selection in a correct staff later)
var track = curScore.selection.elements[0].track;
 
// Do explode.
cmd("explode");
 
// Restore selection in a correct staff.
// This will select only a part of a measure but that seems to be enough
// for explode tool to work.
cmd("next-chord");
while (curScore.selection.elements[0].track > track) {
    cmd("prev-track");
}
cmd("select-next-measure");
cmd("select-prev-chord");

Doing so in a loop will allow running explode tool on every measure separately, although the code above seems to break for me if it encounters a full-measure rest.

The command names suitable for use with cmd() can be found here and correspond to actions available to users via keyboard shortcuts.