1. Method 1

var tree = L5.getCmp('edocOutfileRelationTree');
//Add a selection tree, node automatic collapse
tree.on("click", function(node,e){
node.getUI().toggleCheck(true);
});
tree.root.expand();

2. Method 2

var tree = L5.getCmp('orgstrutree');
//Add a selection tree, node automatic collapse
tree.on("click", function(node,e){
if(node.expanded==false){
node.expand();
}else{
node.collapse();
}
});

Combined use:

var tree = L5.getCmp('orgstrutree');
//Add a selection tree, node automatic collapse
tree.on("click", function(node,e){
var organType = node.record.get("organType");
if(organType == "8"){
node.getUI().toggleCheck(true);
}else{
if(node.expanded==false){
node.expand();
}else{
node.collapse();
}
}
});