Default Settings for "charge" force not clear in documentation please help!!

[gottliebtj]

The code below works as expected unless i change back to the Cloud Nebula layout the change force is still influced from the last change. i cant seem to find what the exact force is out of the box with the generic 3d force graph. please let me know thanks! Great npm package btw 👍

var simulation = graph.forceEngine("d3");
    if(graphLayout == "Cloud Nebula"){
      simulation.d3Force("collision", () => d3.forceCollide().radius(300));

    }else{
      simulation.d3Force("collision", () => d3.forceCollide().radius(300));
      simulation.d3Force("charge", d3.forceManyBody().strength(-30));
    }

also setting it to null just removes the existing force. Im looking for the exact one that is under the hood.