您正在修改节点和链接的数据结构，而不是添加和删除节点，这会扰乱力布局。我特别讨论这些行。

You're modifying the data structures of the nodes and links beyond adding and deleting nodes, which messes up the force layout. I'm talking about these lines in particular.

function bigBang () {
    links = links.concat(linksList);
    nodes = nodes.concat(nodesList);
    buildMolecule();
  }

这个函数的前两行是我在说的。工作jsfiddle 这里。

The first two lines in that function are what I'm talking about. Working jsfiddle here.