is there script to increase duration of composition with included precomps and all layers inside

I need similar for a script I was writing. Probably could be written better but I just pulled the function from a bigger script and patched it to work for you.

app.beginUndoGroup("Change Nested Comp Duration")

var comp = app.project. activeItem;
var mainCompDuration = comp.duration;
var mainCompFrameRate = comp.frameRate; 

changeDuration(comp);

function changeDuration(compToChange) {
    compToChange.duration = mainCompDuration;
    compToChange.frameRate = mainCompFrameRate; //Comment this out if you don't want frame rate to be changed
    for (var i = 1; i <= compToChange.layers.length; i++) {
        compToChange.layers[i].outPoint = mainCompDuration;
        if (compToChange.layers[i].source != null && compToChange.layers[i].source.typeName == "Composition") {
            changeDuration(compToChange.layers[i].source);
        }
    }
}

app.endUndoGroup()

Any questions please ask.

If its all the comps in project you loop through project num items for each get num layers set comp length and layers end point. If it doesnt include all comps in project you do the same but you need a way when looping through project to distinguish the layers you want this to apply to like a prefix in their name