How do I create an array of objects with a nested array based on a similar key?

Issue

I have an array that looks something like this

const example = [
  { id: '1', name: 'Person 1', organization: { id: '11', name: 'Organization A' } },
  { id: '2', name: 'Person 2', organization: { id: '12', name: 'Organization A' } },
  { id: '3', name: 'Person 3', organization: { id: '13', name: 'Organization B' } },
];

As you can see, the organization name is something I want to key off of and create a data structure like this:

const output = [
  // data.value will be their ID
  { 
    organizationName: 'Organization A', 
    data: [
      { label: 'Person 1', value: '1' },
      { label: 'Person 2', value: '2' },
    ],
  },
  { 
    organizationName: 'Organization B', 
    data: [
      { label: 'Person 3', value: '3' },
    ],
  },
]

What I've tried

I know I want to use reduce for something like this, but I feel like I'm off:

const providerOptions = externalPeople.data.reduce((acc, currentValue) => {
  const {
    organization: { name: organizationName },
  } = currentValue;
  if (organizationName) {
    acc.push({ organization: organizationName, data: [] });
  } else {
    const { name: externalPersonName, id } = currentValue;
    acc[acc.length - 1].data.push({ name: externalPersonName, value: id });
  }
  return acc;
}, [] as any);

However the output comes out to something like this:

[
  {organizationName: 'Organization A', data: []},
  {organizationName: 'Organization A', data: []},
  {organizationName: 'Organization B', data: []},
];

data doesn't seem to get anything pushed inside the array in this reduce function, and the organization name get duplicated... what am I doing wrong?

Solution

Easiest way is to use an Map/Set/or object to keep track of orgs you create. This way you are not searching in the array to see if the organization was found already. After you are done, you can create the array you want from the object.

const externalPeople = { 
  data : [
    { id: '1', name: 'Person 1', organization: { id: '11', name: 'Organization A' } },
    { id: '2', name: 'Person 2', organization: { id: '12', name: 'Organization A' } },
    { id: '3', name: 'Person 3', organization: { id: '13', name: 'Organization B' } },
  ],
};

const providerOptions = Object.values(externalPeople.data.reduce((acc, currentValue) => {
  const {
    organization: { name: organizationName },
    name: externalPersonName,
    id
  } = currentValue;

  // Is the org new? Yes, create an entry for it
  if (!acc[organizationName]) {
    acc[organizationName] = { organization: organizationName, data: [] };
  }

  // push the person to the organization
  acc[organizationName].data.push({ name: externalPersonName, value: id });

  return acc;
}, {}));

console.log(providerOptions)

Answered By - epascarello