Group common items together in js

user_6173799 0
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I need to group together all the pId together which has same cId entries. I have the following data -

const data = [{pId:"a", cId: [1,2]}, {pId:"b", cId: [1,2]}, {pId:"c", cId: [3]}];
const data1 = [{pId:"a", cId: [1,2,3]}, {pId:"b", cId: [1,2]}, {pId:"c", cId: [3]}];
const data2 = [{pId:"a", cId: [1,2,3]}, {pId:"b", cId: [1,2,3]}, {pId:"c", cId: [3]}];

Expected output -

data = [{pId:["a","b"], cId: [1,2]}, {pId:["c"],cId: [3]}]
data1 = [{pId:["a","b"], cId: [1,2]}, {pId:["a","c"],cId: [3]}]
data2 = [{pId:["a","b"], cId: [1,2,3]},{pId:["a","b","c"],cId: [3]}]

Please help, in the approach. Kindoff stuck, not able to think which qualifies all the cases

javascript-objects object arrays javascript
1 Answers

From what I can gather you’re looking to group based on array similarity in cId. I think you’re looking at something like this:

function unique (array) {
  return Array.from(new Set(array));
}

function match (cIds) {
  return function (x) {
    return x.cId.join() == cIds;
  }
}

function regroup () {
  return unique(data.map(x => x.cId.join())
    .map(cIds => ({
      pId: data.filter(match(cIds)).map(x => x.pId),
      cId: data.find(match(cIds)).cId
    }));
}

data = regroup(data);
data1 = regroup(data1);
data2 = regroup(data2);

Please note that this is a very naive way of comparing arrays by values (there’s a lot of joins involved). This is not production-code ready, but you get the drift of how to handle this problem.

user_12555270
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