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beforeCollapse

Description​

Fires before collapsing an item

Usage​

beforeCollapse: (
    id: string | number, 
    dir?: string
) => boolean | void;

Parameters​

The callback of the event takes the following parameters:

  • id - (required) the id of an item
  • dir - (optional) the side the children will be hidden in relation to the parent shape ("left" or "right" for type:"topic", otherwise - undefined)

Returns​

Return false to block collapsing an item; otherwise, true

Example​

// initializing Diagram
const diagram = new dhx.Diagram("diagram_container", {
    type: "mindmap"
});
// loading data
diagram.data.parse(data);

// attaching a handler to the event
diagram.events.on("beforeCollapse", (id, dir) => {
    console.log("Collapsing " + diagram.data.getItem(id).text, dir);
    return true;
});

Change log: The dir parameter was added in v3.1

Related article: Event handling