Js recursive function that specified attribute returns it

Question

I am writing the following code which specified the attribute must return it even if it is of type obj, array, string or number.

I'm having some problems getting me back certain attributes going even deeper.

I would like to do this without using external modules.

Can you give me some advice?

function returnElement(obj, label) {
  let pointBool = label.includes(".");
  let arrayOpenBool = label.includes("[");
  let arrayCloseBool = label.includes("]");

  //console.log(obj, label,arrayOpenBool && arrayCloseBool);

  if (arrayOpenBool && arrayCloseBool) {
    let start = label.split("[")[0];
    let number = label.split("[")[1].split("]")[0];
    let end = label.split("]")[0];
    if (label.includes(".")) end = label.split(".")[1];
    return obj[start][number]
      ? returnElement(obj[start][number], end)
      : undefined;
  }

  if (pointBool) {
    let start = label.split(".")[0];
    let end = label.split(".")[1];
    //console.log(obj, label, start, end, obj[end]);
    if (start === "") return obj[end];
    return returnElement(obj[start], end);
  }

  return obj[label];
}


var a = {
  _id: "5d406a179f35ed326a6a5567",
  age: 28,
  name: {first: "James",last: "Bond"},
  user: [{first: "Jon",last: "Witch"},{first: "Myra",last: "Navarro",number:[0,10]}]
};
var b = [];
b.push("item");//undefined
b.push("_id");//5d406a179f35ed326a6a5567
b.push("age");//28
b.push("name.first");//James
b.push("user[1]");//obj{}
b.push("user[1].first");//Myra
b.push("user[2].first");//undefined
b.push("user[1].email");//undefined
b.push("user[0].number");//[0, 1]
b.push("user[1].number[1]");//1

b.forEach(el => {
  console.log(returnElement(a, el));
})

Edit:

Here is an additional thing, given the solution proposed by @NinaScholz, it allows you to sort the data you more parameters, if it can be of use to someone.

based on the following solution: Link

let datatable = [
      {
        _id: '5d406a171ed43384972f04b5',
        index: 0,
        age: 28,
        eyeColor: 'brown',
        name: {
          first: 'Myra',
          last: 'Navarro',
        },
        company: 'SUSTENZA',
        email: '[email protected]',
      },
      {
        _id: '5d406a170db0f4b04d9a9acf',
        index: 1,
        age: 23,
        eyeColor: 'blue',
        name: {
          first: 'Harriett',
          last: 'Tanner',
        },
        company: 'VALPREAL',
        email: '[email protected]',
      },
      {
        _id: '5d406a17e95da8ff80a759c5',
        index: 2,
        age: 39,
        eyeColor: 'blue',
        name: {
          first: 'Vega',
          last: 'Hanson',
        },
        company: 'BEDLAM',
        email: '[email protected]',
      },
      {
        _id: '5d406a175505da190e6875ec',
        index: 3,
        age: 31,
        eyeColor: 'blue',
        name: {
          first: 'Rosemary',
          last: 'Fields',
        },
        company: 'QUAILCOM',
        email: '[email protected]',
      },
      {
        _id: '5d406a17ea96044c027f4e50',
        index: 4,
        age: 27,
        eyeColor: 'brown',
        name: {
          first: 'Dale',
          last: 'Wilkinson',
        },
        company: 'QIAO',
        email: '[email protected]',
      },
      {
        _id: '5d406a17c5fff1ff6653a555',
        index: 5,
        age: 25,
        eyeColor: 'blue',
        name: {
          first: 'Beatrice',
          last: 'Contreras',
        },
        company: 'ZENOLUX',
        email: '[email protected]',
      },
      {
        _id: '5d406a17a199efcba25e1f26',
        index: 6,
        age: 34,
        eyeColor: 'blue',
        name: {
          first: 'Hancock',
          last: 'Wynn',
        },
        company: 'PLASMOS',
        email: '[email protected]',
      },
      {
        _id: '5d406a17019a2a4544a4f134',
        index: 7,
        age: 40,
        eyeColor: 'blue',
        name: {
          first: 'Beatrice',
          last: 'Aston',
        },
        company: 'SNACKTION',
        email: '[email protected]',
      },
      {
        _id: '5d406a17e516dd71af8210d4',
        index: 8,
        age: 39,
        eyeColor: 'blue',
        name: {
          first: 'Barnes',
          last: 'Dunn',
        },
        company: 'PORTALINE',
        email: '[email protected]',
      },
      {
        _id: '5d406a17516936a025b73c33',
        index: 9,
        age: 34,
        eyeColor: 'green',
        name: {
          first: 'Blanche',
          last: 'Cherry',
        },
        company: 'ISOSWITCH',
        email: '[email protected]',
      },
      {
        _id: '5d406a17527a4d2c6a7897dd',
        index: 10,
        age: 33,
        eyeColor: 'blue',
        name: {
          first: 'Gilliam',
          last: 'Farley',
        },
        company: 'AMTAS',
        email: '[email protected]',
      },
      {
        _id: '5d406a175ff11478c416c30b',
        index: 11,
        age: 26,
        eyeColor: 'brown',
        name: {
          first: 'Laura',
          last: 'Short',
        },
        company: 'FISHLAND',
        email: '[email protected]',
      },
      {
        _id: '5d406a1738181b471847339a',
        index: 12,
        age: 20,
        eyeColor: 'brown',
        name: {
          first: 'Moreno',
          last: 'Barber',
        },
        company: 'KEENGEN',
        email: '[email protected]',
      },
      {
        _id: '5d406a17a6bcae6fe3ad1735',
        index: 13,
        age: 30,
        eyeColor: 'brown',
        name: {
          first: 'Fischer',
          last: 'French',
        },
        company: 'INCUBUS',
        email: '[email protected]',
      },
      {
        _id: '5d406a17600ca53e8f63f263',
        index: 14,
        age: 30,
        eyeColor: 'brown',
        name: {
          first: 'Donaldson',
          last: 'Carr',
        },
        company: 'SUNCLIPSE',
        email: '[email protected]',
      },
      {
        _id: '5d406a17530655789a27174f',
        index: 15,
        age: 35,
        eyeColor: 'green',
        name: {
          first: 'Sophia',
          last: 'Payne',
        },
        company: 'PRISMATIC',
        email: '[email protected]',
      },
      {
        _id: '5d406a175dbc687b4c7669d8',
        index: 16,
        age: 34,
        eyeColor: 'green',
        name: {
          first: 'Simone',
          last: 'Pollard',
        },
        company: 'DIGIGEN',
        email: '[email protected]',
      },
      {
        _id: '5d406a179f35ed326a6a5567',
        index: 17,
        age: 28,
        eyeColor: 'green',
        name: {
          first: 'Yvette',
          last: 'Daugherty',
        },
        company: 'CHILLIUM',
        email: '[email protected]',
      },
    ];

function getValue(object, path) {
    return path
        .replace(/\[/g, '.')
        .replace(/\]/g, '')
        .split('.')
        .reduce((o, k) => (o || {})[k], object);
}

function dynamicSort(property) {
    var sortOrder = 1;
    if(property[0] === "-") {
        sortOrder = -1;
        property = property.substr(1);
    }
    return function (a,b) {
        var result = (getValue(a, property) < getValue(b, property)) ? -1 : (getValue(a, property) > getValue(b, property)) ? 1 : 0;
        return result * sortOrder;
    }
}

function dynamicSortMultiple() {
    var props = arguments;
    return function (obj1, obj2) {
        var i = 0, result = 0, numberOfProperties = props.length;
        while(result === 0 && i < numberOfProperties) {
            result = dynamicSort(props[i])(obj1, obj2);
            i++;
        }
        return result;
    }
}

function dynamicSortMultipleRic() {
    var props = arguments;
    return function (obj1, obj2) {
        var i = 0, result = 0, numberOfProperties = props.length;
        while(result === 0 && i < numberOfProperties) result = dynamicSort(props[i++])(obj1, obj2);
        return result;
    }
}

var copyA = Object.assign([], datatable);
var copyB = Object.assign([], datatable);
var copyC = Object.assign([], datatable);

let a = copyA.sort(dynamicSort("name.first"));
let b = copyB.sort(dynamicSortMultiple("name.first","name.last"));
let c = copyC.sort(dynamicSortMultipleRic("name.first","name.last"));


console.log(a,b,c)

@zer00ne: Sorry, I'm not able to understand what you would like to say. I can ask you to be more specific. — Paul
– Paul, Commented Jul 30, 2019 at 19:23
Regex is a set of characters that express a search pattern. Many new developers attempt to use Regex for purposes it wasn't really meant for. You are searching the string representation of an object which is like swimming in mud. — zer00ne
– zer00ne, Commented Jul 30, 2019 at 19:32

Nina Scholz · Accepted Answer · 2019-07-30 19:31:56Z

3

You could replace the brackets and split the string and get the values form the given object.

function getValue(object, path) {
    return path
        .replace(/\[/g, '.')
        .replace(/\]/g, '')
        .split('.')
        .reduce((o, k) => (o || {})[k], object);
}


var a = { _id: "5d406a179f35ed326a6a5567", age: 28, name: { first: "James", last: "Bond" }, user: [{ first: "Jon", last: "Witch" }, { first: "Myra", last: "Navarro", number: [0, 10] }] };

var b = [];

b.push("item");//undefined
b.push("_id");//5d406a179f35ed326a6a5567
b.push("age");//28
b.push("name.first");//James
b.push("user[1]");//obj{}
b.push("user[1].first");//Myra
b.push("user[2].first");//undefined
b.push("user[1].email");//undefined
b.push("user[1].number");//[0, 1]
b.push("user[1].number[1]");//1

b.forEach(el => {
  console.log(getValue(a, el));
});

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Jul 30, 2019 at 19:31

Nina Scholz

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14 Comments

Mark Over a year ago

That's a really nice solution.

Scott Sauyet Over a year ago

I guess I won't post my almost identical solution. Nina, you're just too fast for me!

Paul Over a year ago

@nina: Very interesting as a solution, I was going crazy to solve my solution.

Paul Over a year ago

@ScottSauyet: Publish your solution would be very interesting to see your kind of approach.

Paul Over a year ago

@nina: I didn't understand what you mean by: You could replace the brackets and split the string and get the values form the given object.

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