Export linkDataArray only category Mapping

GoJS
1

I have a treeMap in GoJS and this function:

const exportDiagram = () => {
  const diagram = diagramRef.value
  if (diagram) {
    const json = diagram.model.toJson().replace(/\\"/, '')
    const blob = new Blob([json], { type: 'application/json' })
    const url = URL.createObjectURL(blob)
    const a = document.createElement('a')
    a.href = url
    a.download = 'diagram.json'
    a.click()
    URL.revokeObjectURL(url)
  }
}

which exports the entire diagram. However, I would like to export only the linkDataArray items that are of category “Mapping”. For example:

{"category":"Mapping","from":"ChildFirstName","to":"form1[0].#subform[0].PtAILine5_FirstName[0]"},
{"category":"Mapping","from":"CLsFirstName","to":"form1[0].#subform[0].PtAILine5_FirstName[0]"},
{"category":"Mapping","from":"SpouseFirstName","to":"form1[0].#subform[0].PtAILine5_FirstName[0]"}

How can I do this?

2 
JSON.stringify(myDiagram.model.linkDataArray.filter(d => d.category==="Mapping"))