How to compare if, 2 separate Objects/Array have one same element and concat 2 objects into one array, if there is matching element? Javascript

Question

I have a promise.all that returns 2 objects. The common element in these 2 seperate objects is room. I want both object to be in 1 array, and if the room matches, I would like to concat the objects.

const urls = ['/room/*/userconfig', '/room/*/observation/latest'];
let requests = urls.map(url => axios.get(url)); 

Promise.all(requests)
  .then(res => {
        let patientObjArray = Object.values(res[0].data);
        let patientObservationsArray = Object.values(res[1].data);
  })


const patientObjArray = [
  {
    room: "room18",
    patient: "91911671-302b-47b5-a24d-d2a1fea548d6",
    hospitalNumber: "12"
  },
  {
    room: "room19",
    patient: "b793bbba-b2bb-4995-9247-bb4d4f2be65a",
    hospitalNumber: "13"
  },
  {
    room: "room20",
    patient: "a8e8efa1-ea00-4d32-b4b2-58727200b9b0",
    hospitalNumber: "14"
  },
  {
    room: "room21",
    patient: "asdadddaddada-b4badasd2-7272a00qb9b0",
    hospitalNumber: "15"
  }
];

// patientObservationsArray is data related to patientObjArray.room

const patientObservationsArray = [
  {
    observation: {
      room: "room18",
      timestamp: "10:00",
      patient: "91911671-302b-47b5-a24d-d2a1fea548d6"
    },
    comment: { value: "Ok" }
  },
  {
    observation: {
      room: "room19",
      timestamp: "11:00",
      patient: "b793bbba-b2bb-4995-9247-bb4d4f2be65a"
    },
    comment: { value: "Good" }
  },
  {
    observation: {
      room: "room20",
      timestamp: "12:00",
      patient: "a8e8efa1-ea00-4d32-b4b2-58727200b9b0"
    },
    comment: { value: "bad" }
  }
];

expected output

const combinedArray = [
  {
    room: "room18",
    patient: "91911671-302b-47b5-a24d-d2a1fea548d6",
    hospitalNumber: "12",
    timestamp: "10:00",
    comment: "Ok"
  },
  {
    room: "room19",
    patient: "b793bbba-b2bb-4995-9247-bb4d4f2be65a",
    hospitalNumber: "13",
    timestamp: "11:00",
    comment: "Good"
  },
  {
    room: "room20",
    patient: "a8e8efa1-ea00-4d32-b4b2-58727200b9b0",
    hospitalNumber: "14",
    timestamp: "12:00",
    comment: "Bad"
  },
  {
    room: "room21",
    patient: "asdadddaddada-b4badasd2-7272a00qb9b0",
    hospitalNumber: "15"
  }
];

TopW3 · Accepted Answer · 2019-11-25 16:58:17Z

1

Here is my solution. Please try this code.

const mergedArray = patientObjArray.map(obj => {
    const matched = patientObservationsArray.find(obs => obs.observation.room === obj.room);
    if (!!matched) {
        return { ...obj, ...matched.observation, comment: matched.comment.value };
    } else {
        return obj;
    }
});

console.log(mergedArray);

answered Nov 25, 2019 at 16:58

TopW3

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3 Comments

Jereme Over a year ago

Hi did you mean to use double !!matched?

TopW3 Over a year ago

!! returns always boolean value. It doesn't affect the result of the above code(automatically converted to boolean), but that is a more clear code. In certain cases(like react.js app), !! is needed.

Jereme Over a year ago

doesn if(matched) check work because it is boolean?

junwen-k · Accepted Answer · 2019-11-25 16:37:26Z

You can first flatten your patientObservationsArray, then merge it with your patientObjArray and finally use reduce method to merge your array.

There are probably better ways of doing this, feel free to give me suggestions. This should solve your problem.

const patientObjArray = [
  {
    room: "room18",
    patient: "91911671-302b-47b5-a24d-d2a1fea548d6",
    hospitalNumber: "12"
  },
  {
    room: "room19",
    patient: "b793bbba-b2bb-4995-9247-bb4d4f2be65a",
    hospitalNumber: "13"
  },
  {
    room: "room20",
    patient: "a8e8efa1-ea00-4d32-b4b2-58727200b9b0",
    hospitalNumber: "14"
  },
  {
    room: "room21",
    patient: "asdadddaddada-b4badasd2-7272a00qb9b0",
    hospitalNumber: "15"
  }
];

const patientObservationsArray = [
  {
    observation: {
      room: "room18",
      timestamp: "10:00",
      patient: "91911671-302b-47b5-a24d-d2a1fea548d6"
    },
    comment: { value: "Ok" }
  },
  {
    observation: {
      room: "room19",
      timestamp: "11:00",
      patient: "b793bbba-b2bb-4995-9247-bb4d4f2be65a"
    },
    comment: { value: "Good" }
  },
  {
    observation: {
      room: "room20",
      timestamp: "12:00",
      patient: "a8e8efa1-ea00-4d32-b4b2-58727200b9b0"
    },
    comment: { value: "bad" }
  }
];

const combinedArray = patientObservationsArray
  // flatten your patientObservationsArray
  .map(item => ({ ...item.observation, ...item.comment }))
  // concat to your patientObjArray
  .concat(patientObjArray)
  // use reduce method to merge your array
  .reduce((res, item) => {
    const { room } = item;
    const index = res.findIndex(i => i.room === room);
    if (index > -1) {
      // merge object if already exists
      res[index] = { ...res[index], ...item };
    } else {
      // else push into your array
      res.push(item);
    }
    return res;
  }, []);

console.log(combinedArray);

Aino · Accepted Answer · 2019-11-25 17:40:58Z

0

Here is a playcode plunkr for my suggestion: https://playcode.io/473861?tabs=script.js,preview,console

We simply loop through the first array, run every object through a matching function against the second array and add the objects into a new array. If a match is found the required fields are added.

I would suggest keeping the object structure similar just to make using the objects in new data easier.

answered Nov 25, 2019 at 17:40

Aino

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