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Accepted
Eduardo Jiménez
Asked: 2022-09-08 21:54:52 +0800 CST 2022-09-08 21:54:52 +0800 CST

From a JSON Array create a new JSON from the union of a property in an array

  • 772

I have a JSON with a format similar to this:

[{
  "email": "[email protected]",
  "school_id": 1,
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 1
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 1
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 2,
  "school": "Escuela 2"
}];

And I would like to create a New JSON that joins the school_id and school properties into a new property called schools which would be an array of[{school_id: number, school: string}]

I would like to make use of functional programming, however, I still can't find the correct way to achieve this:

[{
    "email": "[email protected]",
    "schools": [{
        "school_id": 1,
        "school": "Escuela 1"
      } {
        "school_id": 2,
        "school": "Escuela 2"
      }
    },
    {
      "email": "[email protected]",
      "schools": [{
        "school_id": 1,
        "school": "Escuela 1"
      }]
    },
    {
      "email": "[email protected]",
      "schools": [{
        "school_id": 1,
        "school": "Escuela 1"
      }]
}];

So far I have tried this:

let results = [{
  "email": "[email protected]",
  "school_id": 1,
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 1,
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 1,
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 2,
  "school": "Escuela 2"
}];

results.forEach((result, idx) => {
  if (results.findIndex(el => el.email === result.email) > idx) {
    result.schools.push(results.filter((el, index) => el.email === result.email && index > idx));
    delete result.schools.email;
    delete result.school_id;
  } else {
    result.schools = [{
      school_id: result.school_id,
      school: result.school
    }]
    delete result.school_id;
    delete result.school;
  }
});
console.log(results);
console.log(JSON.stringify(results));

javascript

2 Answers

  1. Best Answer

    try these changes to make it work for you

    let results = [{
  "email": "[email protected]",
  "school_id": 1,
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 1,
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 1,
  "school": "Escuela 1"
}, {
  "email": "[email protected]",
  "school_id": 2,
  "school": "Escuela 2"
}];


function unifyEmails(arr) {
  let unifiedResult = [];

  for (let i = 0; i < arr.length; i++) {
    let currentEmail = unifiedResult.find(e => e['email'] === arr[i]['email']);
    if (currentEmail) {
      currentEmail['schools'].push({
        'school_id': arr[i]['school_id'],
        'school': arr[i]['school']
      });
    } else {
      unifiedResult.push({
        'email': arr[i]['email'],
        'schools': [{
          'school_id': arr[i]['school_id'],
          'school': arr[i]['school']
        }]
      });
    }
  }

  return unifiedResult;
}


console.log(unifyEmails(results))

    What this code does is save the current object if it doesn't already exist in the array, otherwise it just adds the school.

    • 1

  2. This may be a way for what you are looking for:

    const model = [{ 
    "email": "[email protected]", 
    "school_id": 1, 
    "school": "Escuela 1" 
}, { 
    "email": "[email protected]", 
    "school_id": 1,
    "school": "Escuela 1" 
}, { 
    "email": "[email protected]", 
    "school_id": 1,
    "school": "Escuela 1" 
}, { 
    "email": "[email protected]", 
    "school_id": 2, 
    "school": "Escuela 2" 
}];

//creamos un nuevo modelo
let newModel = [];

//recorremos el json
for(let x = 0; x < model.length ; x++){
    //insertamos los parametros del nuevo modelo
    let index = newModel.length;
    newModel[index] = {email : '' , schools : []};
    newModel[index].email = model[x].email;
    newModel[index].schools[newModel[x].schools.length] = { school_id : model[x].school_id, school : model[x].school };

    //obtenemos el correo de la posicion actual y
    //recorremos nuevamente buscando si existe el correo en nuestro modelo actual.
    for(let y = 0; y < x; y++){
        //si encontramos una coincidencia en los correos añadimos los parametros de schools a el.
        if(newModel[y].email == model[x].email){
            newModel[y].schools[newModel[y].schools.length] = { school_id : model[x].school_id, school : model[x].school };
            //borramos el objeto previamente creado y salimos de esta ejecución
            delete newModel[index];
            break;
        }
    }
}
console.log(newModel);

    I hope it works for you

    • 1