B4J Code Snippet [BANano] Map Get / Put Recursively ... perhaps a B4X wish...

Ola

With the jsPDF library that i'm using, the data structures are deeply imbedded, for example.

data.cell.styles.textColor = [0. 255. 50]

So I was thinking, what if one was able to recursively execute a map get/set using a path?

In normal circumstances to create a map object like this tree structure (image from console.log)

One has to write source code like this..

Dim m As Map = CreateMap()
    Dim user As Map = CreateMap()
    Dim address As Map = CreateMap()
    address.Put("addressline1", "")
    address.Put("addressline2", "")
    address.Put("city", "")
    address.Put("province", "")
    address.Put("country", "")
    user.put("firstname", "")
    user.Put("lastname", "")
    user.Put("address", address)
    m.Put("user", user)

Comes in RecursivePut... (for BANano)

Sub RecursivePut(data As Map, path As String, value As Object)
    Dim prevObj As BANanoObject = data
    Dim items As List = BANano.Split(".", path)
    Dim iTot As Int = items.Size
    Dim iCnt As Int
    '
    Dim strprev As String = ""
    Dim prtObj As BANanoObject
    Dim litem As String = items.Get(iTot - 1)
    '
    For iCnt = 1 To iTot - 1
        'get the previos path
        strprev = items.Get(iCnt - 1)
        'the parent object
        prtObj = prevObj.GetField(strprev)
        'this does not exist, create it
        If BANano.IsUndefined(prtObj) Then
            Dim no As Object
            prevObj.SetField(strprev, no)
            prevObj = prevObj.GetField(strprev)
        Else
            prevObj = prtObj
        End If
    Next
    prevObj.SetField(litem, value)
End Sub

So if we run this example, even, if the map is initialized empty

Dim m as Map = CreateMap()
RecursivePut(m, "user.firstname", "Anele")
    RecursivePut(m, "user.lastname", "Mbanga")
    RecursivePut(m, "user.address.addressline1", "40.71")
    RecursivePut(m, "user.address.addressline2", "-73.98")
    RecursivePut(m, "user.address.city", "Moon Colony")
    RecursivePut(m, "user.address.province", "Close to Mars")
    RecursivePut(m, "user.address.country", "Outer Space")
    RecursivePut(m, "user.firstname", "Ozzie")
    RecursivePut(m, "user.loves", "B4X")

We get (image from console.log)

Imma try and get the Get working....

Enjoy!

 

[alwaysbusy]

A nice idea. Maybe this can give you some inspiration for the GET (e.g. to use wildcards and queries):

JSONPath with JavaScript | JSON tutorial| w3resource

JSONPath is a lightweight library to find and extract sections from a JSON data. In this page you will learn how to work with JSONPath and JavaScript.

www.w3resource.com

PS: BANanoShared.StrParse is just BANAno.Split but returns a List and not (), same thing anyway.

What error do you get if you use a list? Looks fine with this code:

Dim splList As List = BANano.Split(".", "alain.is.here")
For i = 0 To splList.Size - 1
        Log(splList.Get(i))
Next

' result:
alain
is
here

Alwaysbusy

 

[Mashiane]

Let's Recursively get map items

RecursiveGet(m, "user.loves")

Returns B4X

RecursiveGet(m, "user.address.country")
Outer Space

RecursiveGet(m, "user")

{
address: {addressline1: "40.71", addressline2: "-73.98", city: "Moon Colony", province: "Close to Mars", country: "Outer Space"}
firstname: "Ozzie",
lastname: "Mbanga",
loves: "B4X"}

RecursiveGet(m, "user.address")

Here is the sub

Sub RecursiveGet(data As Map, path As String) As Object
    Dim prevObj As BANanoObject = data
    Dim items As List = BANano.Split(".", path)
    Dim iTot As Int = items.Size
    Dim iCnt As Int
    '
    Dim strprev As String = ""
    Dim prtObj As BANanoObject
    Dim litem As String = items.Get(iTot - 1)
    '
    For iCnt = 1 To iTot - 1
        'get the previos path
        strprev = items.Get(iCnt - 1)
        'the parent object
        prtObj = prevObj.GetField(strprev)
        'this does not exist, return
        If BANano.IsUndefined(prtObj) Then
            Return Null
        Else
            prevObj = prtObj
        End If
    Next
    Dim res As Object = prevObj.GetField(litem)
    Return res
End Sub

Ta!

 

[Mashiane]

What error do you get if you use a list? Looks fine with this code:

Updated the code to use BANAno.Split. Thx,.