[
{
"NodeId": 1,
"HierarchyLevel": 1,
"type": "folder",
"nodes": [
{
"NodeId": 2,
"HierarchyLevel": 2,
"type": "folder",
"nodes": [
{
"NodeId": 3,
"HierarchyLevel": 3,
"type": "category"
}
]
},
{
"NodeId": 4,
"HierarchyLevel": 2,
"type": "category",
"nodes": [
{
"NodeId": 5,
"HierarchyLevel": 3,
"type": "file"
}
]
}
]
},
{
"NodeId": 6,
"HierarchyLevel": 1,
"type": "folder",
"nodes": [
{
"NodeId": 7,
"HierarchyLevel": 2,
"type": "category"
}
]
}
]
My task was to get rid of every Node which has no subnodes of type file at the last level of the hierachy. So for this example the result I needed was an array containing only the nodes 1,2,4,5.
Of course in reality the nested structure was way more complex. My approach was a recursive function which checks every element’s type and nodes length property and calls itself if there are any subnodes. Also it is recommended to loop backwards through the array while deleting from it.
const removeEmptyNodes = nodes => {
for (let i = nodes.length - 1; i > -1; i--) {
const n = nodes[i]
//call function recursive to go deeper through the nested structure
if (n.nodes) removeEmptyNodes(n.nodes)
//remove element if it's not a file and has no subnodes
if (n.type !== 'file' && (!n.nodes || n.nodes.length === 0)) nodes.splice(i, 1)
}
}
// nodes contains the array data from above
removeEmptyNodes(nodes)
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