map array with more than one object into another array

Question

This is the original Array: It can have one or more objects. In each object there is an adress and an array of mitglieder.

    const original = [
    {
      "adresse":{
        "strasse":"Streetone",
        "plz":"55555",
        "ort":"Hamburg",
        "xy": "aaaaaa"
      },
      "mitglieder":[
        {
          "zugestimmt":true,
          "nummer":"345",
          "nachname":"Meier",
          "vorname":"Peter",
          "geburtsDatum":"1980-01-01"
        },
        {
          "zugestimmt":true,
          "nummer":"435",
          "nachname":"Haushalt",
          "vorname":"Anderer",
          "geburtsDatum":"1980-01-01"
        },
      ]
    },
    {
      "adresse":{
        "street":"Streettwo",
        "plz":"34444",
        "ort":"Hamburg",
        "xy": "bbbbb"
      },
      "mitglieder":[
        {
          "zugestimmt":true,
          "nummer":"345",
          "nachname":"Muster",
          "vorname":"Maria",
          "geburtsDatum":"1980-01-01",
          "xy" : {a:'1', b:'2'}
        },
        {
          "zugestimmt":true,
          "nummer":"345",
          "nachname":"Muster",
          "vorname":"Maria",
          "geburtsDatum":"1980-01-01",
          "xy" : {a:'1', b:'2'}
        },
      ]
    }
  ];

And I want to map it into this Array: This should be an array of the mitglieder of all the objects from the original array. The street, plz and ort ist from the adress key. The "arrayIwant" should only have these properties not the property"xy" or other that can be in the original array.

let arrayIwant = [
    {
    vorname: original[0].mitglieder[0].vorname,
    nachname: original[0].mitglieder[0].nachname,
    geburtsdatum: original[0].mitglieder[0].geburtsDatum,
    zugestimmt: original[0].mitglieder[0].zugestimmt,
    strasse: original[0].adressse.street,
    plz: original[0].adresse.plz,
    ort: original[0].adresse.ort,
    
  },
  {
     vorname: original[0].mitglieder[1].vorname,
    nachname: original[0].mitglieder[1].nachname,
    geburtsdatum: original[0].mitglieder[1].geburtsDatum,
    zugestimmt: original[0].mitglieder[1].zugestimmt,
    strasse: original[0].adresse.street,
    plz: original[0].adresse.plz,
    ort: original[0].adresse.ort,
  },
  {
    vorname: original[1].mitglieder[0].vorname,
    nachname: original[1].mitglieder[0].nachname,
    geburtsdatum: original[1].mitglieder[0].geburtsDatum,
    zugestimmt: original[1].mitglieder[0].zugestimmt,
    strasse: original[1].adresse.street,
    plz: original[1].adresse.plz,
    ort: original[1].adresse.ort,
  },
  {
    vorname: original[1].mitglieder[1].vorname,
    nachname: original[1].mitglieder[1].nachname,
    geburtsdatum: original[1].mitglieder[1].geburtsDatum,
    zugestimmt: original[1].mitglieder[1].zugestimmt,
    strasse: original[1].adresse.street,
    plz: original[1].adresse.plz,
    ort: original[1].adresse.ort,
  }
 ]

thanks for your help

I’m voting to close this question because the author showed no attempts at a solution, and thus the question reads like a homework question. — dayuloli, Sep 19 '22 at 22:38

PeterKA · Accepted Answer · 2022-09-20T00:29:15.350

Use Array#flatMap and Array#map with the spread operator as follows:

const 
    original = [ { "adresse":{ "street":"Streetone", "plz":"55555", "ort":"Hamburg" }, "mitglieder":[ { "zugestimmt":true, "nummer":"345", "nachname":"Meier", "vorname":"Peter", "geburtsDatum":"1980-01-01" }, { "zugestimmt":true, "nummer":"435", "nachname":"Haushalt", "vorname":"Anderer", "geburtsDatum":"1980-01-01" }, ] }, { "adresse":{ "street":"Streettwo", "plz":"34444", "ort":"Hamburg" }, "mitglieder":[ { "zugestimmt":true, "nummer":"345", "nachname":"Muster", "vorname":"Maria", "geburtsDatum":"1980-01-01" }, { "zugestimmt":true, "nummer":"345", "nachname":"Muster", "vorname":"Maria", "geburtsDatum":"1980-01-01" }, ] } ],

    output = original.flatMap(
        ({adresse,mitglieder}) => 
            mitglieder.map(mitg => delete mitg.nummer && ({...mitg,...adresse}))
    );

    console.log( output );

Alternatively .... .. .

You may have to list all the desired sub-properties from the two properties as show in this demo. In the process you can alias any property whose name you would like to change for example to change street to strasse alias like so: street:strasse then use strasse in the final object as shown.

const 
    original = [ { "adresse":{ "street":"Streetone", "plz":"55555", "ort":"Hamburg", "xy": "aaaaaa" }, "mitglieder":[ { "zugestimmt":true, "nummer":"345", "nachname":"Meier", "vorname":"Peter", "geburtsDatum":"1980-01-01" }, { "zugestimmt":true, "nummer":"435", "nachname":"Haushalt", "vorname":"Anderer", "geburtsDatum":"1980-01-01" }, ] }, { "adresse":{ "street":"Streettwo", "plz":"34444", "ort":"Hamburg", "xy": "bbbbb" }, "mitglieder":[ { "zugestimmt":true, "nummer":"345", "nachname":"Muster", "vorname":"Maria", "geburtsDatum":"1980-01-01", "xy" : {a:'1', b:'2'} }, { "zugestimmt":true, "nummer":"345", "nachname":"Muster", "vorname":"Maria", "geburtsDatum":"1980-01-01", "xy" : {a:'1', b:'2'} }, ] } ],

    output = original.flatMap(
        ({
            adresse: {street: strasse,plz,ort},
            mitglieder //still an array of objects, so wait ...
        }) =>
        mitglieder.map(
            //now you have an object, so you can list the desired props:
            ({vorname,nachname,geburtsDatum,zugestimmt}) =>
            ({vorname,nachname,geburtsDatum,zugestimmt,strasse,plz,ort})
        )
    );

    console.log( output );

Thanks PeterKA, but the property "xy" or others that are not in the "arrayIwant" should not be in the "arrayIwant". — Koga, Sep 19 '22 at 22:41
You can either delete as shown or just list the properties you want. Looks like you changed the question once answers were provided. You may want to show us what you have done so far before we can update our answers. Give it a try; you now at least have a clue. — PeterKA, Sep 19 '22 at 22:44
Thanks PeterKa, i have done a map on the Output Array to get only the props i need, see below. — Koga, Sep 19 '22 at 23:18

Tibrogargan · Answer 2 · 2022-09-19T22:38:02.237

This is straightforward. You want to create a new object for every element of the mitglieder array in every element of your original array.

 let original = [
   { "adresse":{ "street":"Streetone", "plz":"55555", "ort":"Hamburg", "xy": "aaaaaa" }
   , "mitglieder":
     [ { "zugestimmt":true, "nummer":"345", "nachname":"Meier", "vorname":"Peter", "geburtsDatum":"1980-01-01" }
     , { "zugestimmt":true, "nummer":"435", "nachname":"Haushalt", "vorname":"Anderer","geburtsDatum":"1980-01-01" },
     ]
   },
   { "adresse":{ "street":"Streettwo", "plz":"34444", "ort":"Hamburg", "xy": "aaaaab"}
   , "mitglieder":
     [ { "zugestimmt":true, "nummer":"345", "nachname":"Muster", "vorname":"Maria", "geburtsDatum":"1980-01-01" }
     , { "zugestimmt":true, "nummer":"345", "nachname":"Muster", "vorname":"Maria", "geburtsDatum":"1980-01-01" },
     ]
   }
]

let adressePropMap = { 'street': 'strasse', 'plz': 'plz', 'ort': 'ort' }
myArray = original.reduce( (accum, elem) => {
  elem.mitglieder.forEach( (mitglieder) => {
    obj = {}                         // create the new object
    for (const[from, to] of Object.entries(adressePropMap )) {
      obj[to] = elem.adresse[from]
    }
    Object.assign(obj, mitglieder)   // copy the mitglieder properties
    delete obj.nummer                // remove unwanted property
    accum.push(obj)                  // put the new object into the accumulator
  })
  return accum
}, [])

console.log(myArray)

Thanks, its nearly what i wanted but not exactly. The original Array can have properties, that the "arrayIwant" should not have. I have edit the original Array above, with the props 'xy'. These props or other props that can be in the original array should not be in the ""arrayIwant". https://stackoverflow.com/users/2487517/tibrogargan — Koga, Sep 19 '22 at 22:23
If what you're asking for is not what you want, please don't complain that you didn't get what you wanted. You got what you asked for. — Tibrogargan, Sep 19 '22 at 22:28
Sorry my fault, should i open another question and mark this as solve, what do you suggest? — Koga, Sep 19 '22 at 22:31
I've updated it so it maps only specific properties for `adresse`, but yeah - in future try and not move the goal posts mid-game. You might want to consider using a similar technique for copying the properties from `mitglieder`. Copying everything and removing one is fairly trivial, but it could start presenting design/maintenance issues if you want to modify multiple fields — Tibrogargan, Sep 19 '22 at 22:39

map array with more than one object into another array

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