I am receiving an Array of Objects like so

[
    {
       "payload":{
          "correlation":{
             "metadata":{
                "customerId":"12345",
                "project":"Project One"
             }
          }
       }
    },
    {
       "payload":{
          "correlation":{
             "metadata":{
                "customerId":"12345",
                "project":"Project Two"
             }
          }
       }
    },
    {
       "payload":{
          "correlation":{
             "metadata":{
                "customerId":"12345",
                "project":"Project Two"
             }
          }
       }
    },
    {
       "payload":{
          "correlation":{
             "metadata":{
                "customerId":"54323",
                "project":"Project One"
             }
          }
       }
    }
]

What I am trying to do is count all the unique customerId's per project. So for the above data, I would expect

Project One: 2
Project Two: 1 //because 12345 is shown twice for Project Two, we only want unique so count it as 1

So I can do the counts using a map, something like this

const lutProjects = new Map();
Object.entries(data).forEach(([key, value]) => {
  const project = value?.payload?.correlation?.metadata?.project;
  const custId = value?.payload?.correlation?.metadata?.customerId;
  
  lutProjects.set(project, (lutProjects.get(project) || 0)   1);
});

However, this does not handle unique ids for each project, so outputs 2 and 2.

How can I also handle unique id's per project?

I have created a JSFiddle

Thanks

CodePudding user response：

If you use reduce() to create an object with the project as key, and the value as an array containing the customerId, we can use includes() to check if this customerId is already known, and only add it to the array if not.

Then, we can use a second reduce() to change the array ow customerId's to the length of the array:

const data = [{"payload":{"correlation":{"metadata":{"customerId":"12345", "project":"Project One"} } } }, {"payload":{"correlation":{"metadata":{"customerId":"12345", "project":"Project Two"} } } }, {"payload":{"correlation":{"metadata":{"customerId":"12345", "project":"Project Two"} } } }, {"payload":{"correlation":{"metadata":{"customerId":"54323", "project":"Project One"} } } } ];

let res = data.reduce((prev, cur) => {
    const { customerId, project } = cur.payload.correlation.metadata;
    if (!prev[project]) prev[project] = [];
    if (!prev[project].includes(customerId)) {
      prev[project].push(customerId);
    }
    return prev;
}, {});
res = Object.keys(res).reduce((prev, cur) => ({ ...prev, [cur]: res[cur].length }), {});

console.log(res);

{
  "Project One": 2,
  "Project Two": 1
}

CodePudding user response：

You can try quick fix with below snippet

let data = [{"payload":{"correlation":{"metadata":{"customerId":"12345","project":"Project One"}}}},{"payload":{"correlation":{"metadata":{"customerId":"12345","project":"Project Two"}}}},{"payload":{"correlation":{"metadata":{"customerId":"12345","project":"Project Two"}}}},{"payload":{"correlation":{"metadata":{"customerId":"54323","project":"Project One"}}}}]

data = Array.from(new Set(data.map(f => f.payload.correlation.metadata.project))).map(d => {
   return {
      [d]: [...new Set(data.filter(f => f.payload.correlation.metadata.project === d).map(c => c.payload.correlation.metadata.customerId))].length
   }
});

console.log(data);

CodePudding user response：

Use the reduce method in combination with an array of unique ids for each project, then use length on those array to know the final count. Here is my proposition:

const arr = [
    {
       "payload":{
          "correlation":{
             "metadata":{
                "customerId":"12345",
                "project":"Project One"
             } 
          }
       }
    },
    {
       "payload":{
          "correlation":{
             "metadata":{
                "customerId":"12345",
                "project":"Project Two"
             }
          }
       }
    },
    {
       "payload":{
          "correlation":{
             "metadata":{
                "customerId":"12345",
                "project":"Project Two"
             }
          }
       }
    },
    {
       "payload":{
          "correlation":{
             "metadata":{
                "customerId":"54323",
                "project":"Project One"
             }
          }
       }
    }
]

const cb = (accumulator, { payload }) => {
    const { project, customerId } = payload.correlation.metadata
    if (!accumulator[project]) {
      return { ...accumulator, [project]: [customerId] }
    }
    else if (accumulator[project] && accumulator[project].indexOf(customerId) === -1) {
    return { ...accumulator, [project]: [...accumulator[project], customerId] }
    } else return accumulator
}

const initialAccumulator = {}

const result1 = arr.reduce(cb, initialAccumulator)
const result2 = Object.keys(result1).map(key => ({ [key]: result1[key].length }))
console.log(result2)