How to combinine the content of multiple objects inside an array where there is the same key-CodePudding

I want to combine the content of multiple objects inside an array that have the same key and join the content in one array.

I have the following array of object and I need to join in one array the content key value when I have AT_CALLCENTER or AT_SITE

[
  {
    candidateId: 'DEMO-000031',
    content: 'test',
    stage: 'AT_CALLCENTER'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'test',
    stage: 'AT_CALLCENTER'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'Hello Alex',
    stage: 'AT_CALLCENTER'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'test',
    stage: 'AT_CALLCENTER'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'ttests',
    stage: 'AT_SITE'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'test',
    stage: 'AT_SITE'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'testest',
    stage: 'AT_SITE'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'test',
    stage: 'AT_SITE'
  }
]

Expected result

{
  "AT_CALLCENTER": ["test", "test", "Hello Alex", "test"],
  "AT_SITE": ["ttests", "...", "..."]
}

The result above shows that I need to have in one array all the content of the original object under the same key AT_CALLCENTER or AT_SITE

CodePudding user response：

You can use Array#reduce to do this:

data.reduce(
  (obj, { stage, content }) => (
    (stage in obj
      ? obj[stage].push(content) // if object property is already defined, push
      : (obj[stage] = [content]) // otherwise create a new property
    ),
    obj
  ),
  {} // start off with an empty object
);

const data = [{
    candidateId: 'DEMO-000031',
    content: 'test',
    stage: 'AT_CALLCENTER'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'test',
    stage: 'AT_CALLCENTER'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'Hello Alex',
    stage: 'AT_CALLCENTER'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'test',
    stage: 'AT_CALLCENTER'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'ttests',
    stage: 'AT_SITE'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'test',
    stage: 'AT_SITE'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'testest',
    stage: 'AT_SITE'
  },
  {
    candidateId: 'DEMO-000031',
    content: 'test',
    stage: 'AT_SITE'
  }
];

const result = data.reduce((obj, { stage, content }) => ((stage in obj ? obj[stage].push(content) : (obj[stage] = [content])), obj), {});
console.log(result);

CodePudding user response：

As in the previous answer, you could use a reduce function to accomplish what you want. The spread syntax can help it be done in a declarative manner, like so:

data.reduce((val,item) => (
    {...val, [`${item.stage}`]: [...(val[item.stage] || []), item.content]}
), {});