Homelab, Linux & ABAP (~˘▾˘)~
 

[PDF.js] Allow PDF documents to disable copying in the viewer

With pull request 11789, the PDF Viewer respects the PDF property Content Copying, if the viewer option enablePermissions is set to true.

I’ve embedded my viewer in an iFrame like this:

<iframe id="pdf-js-viewer" src="/pdf/web/viewer.html" title="webviewer" frameborder="0" width="100%" height="700" allowfullscreen="" webkitallowfullscreen=""/>

The enablePermissions property can be modified using the PDFViewerApplicationOptions.set() function. The property has to be set before the Viewer is initialized. To archive this, you can listen to the event webviewerloaded (read more about it here).

                document.addEventListener("webviewerloaded", async () => {
                    let pdfViewerIFrame = document.getElementById("pdf-js-viewer")
                    pdfViewerIFrame.onload = () => {
                        //https://github.com/mozilla/pdf.js/blob/master/web/app_options.js
                        pdfViewerIFrame.contentWindow.PDFViewerApplicationOptions.set("enablePermissions", true) //allow PDF documents to disable copying in the viewer
                        pdfViewerIFrame.contentWindow.PDFViewerApplicationOptions.set("defaultUrl", "") //prevent loading default pdf
                    }
                })

[JavaScript] Find specific object from an array of nested objects

I was again working on a task for my hierarchical tree structure (see previous post here). This time I needed to find a specific object with a specific property value.

So here again my nested array:

const aTreeData = [{
    "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"
    }]
  }
]

I needed a function that was able to find any object by providing only the NodeId value. Fortunately I stumbled accross some excellent code snippet by Scott Sauyet which is exactly doing what I needed:

https://stackoverflow.com/questions/68559392/find-object-from-an-array-of-nested-objects-by-key-in-javascript

I just had to change the properties to match my objects and it was working!

const findNodeInTreeData = (aTreeData, nodeId) => {
  const deepFind = pred => ([x, ...xs] = []) =>
    x && (pred(x) ? x : deepFind(pred)(x.nodes) || deepFind(pred)(xs))

  const findByNodeId = id => obj =>
    deepFind(o => o.NodeId == id)([obj])

  return findByNodeId(nodeId)(aTreeData[0])
}

console.log(findNodeInTreeData(aTreeData, 5))

[JavaScript] Itereate through array of nested objects and delete specific objects

[
    {
        "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)

[SAPUI5] Get and set properties of a binded model and submit changes

Get:

const oModel = this.getView().getModel()
const sPath = this.getView().getBindingContext().sPath
const sID = oModel.getProperty(sPath+"/ID")

Set:

const newID = "12345"
oModel.setProperty(sPath+"/ID", newID)

When using the set property function, you can now submit your changes this way:

        // First check if there are any changes    
        if (!oModel.hasPendingChanges()) {
           MessageToast.show("Nothing to do!")
           return
        }
        
        // Now submit your changes
        oModel.submitChanges({
          success: () => MessageToast.show("Success!"),
          error: (err) => alert(err)
        })

This way is much more comfortable, than using oModel.update().