create complex table from the JSON data for multiple items

Question

I have a JSON that looks like this

[{
                "teacher": "teacher1",
                "student": "student1",
                "segment": "product"
            },
            {
                "teacher": "teacher1",
                "student": "student1",
                "segment": "UNR"
            },
            {
                "teacher": "teacher1",
                "student": "student1",
                "segment": "product"
            },
            {
                "teacher": "teacher2",
                "student": "student1",
                "segment": "UNR"
            },
            {
                "teacher": "teacher2",
                "student": "student2",
                "segment": "product"
            }
        ]

With the help of create complex table from the Json data i can create an array counting each teacher and its count by I want to add another detail in it now. I want to calculate the instance of the segment for each teacher as well like below

[
    {
        "teacherName": "teacher1",
        "teacherCount": "3",
        "productCount":"2",
        "unrCount":"1"
    },
    {
        "teacherName": "teacher2",
        "teacherCount": "2",
        "productCount":"1",
        "unrCount":"1"
    }
]

Answer 1

let say d is your json, then this code will work.

d.reduce((s, i)=>{
    teacher=i["teacher"]
    t=(s[teacher]==null)?{teacherCount:0}:s[teacher]
    seg=i['segment']
    t[seg]=(t[seg]==null)?1:(t[seg]+1)
    t["teacherCount"]+=1
    s[teacher]=t
    return s
},{})

Answer 2

One option is using reduce to loop thru the array. Use teacher as the key to summarize the data into an object. Use Object.values to convert object into an array.

 const data = [{"teacher":"teacher1","student":"student1","segment":"product"},{"teacher":"teacher1","student":"student1","segment":"UNR"},{"teacher":"teacher1","student":"student1","segment":"product"},{"teacher":"teacher2","student":"student1","segment":"UNR"},{"teacher":"teacher2","student":"student2","segment":"product"}] const result = Object.values(data.reduce((c, {teacher,segment}) => { c[teacher] = c[teacher] || {"teacherName": teacher,"teacherCount": 0,"productCount": 0,"unrCount": 0}; c[teacher].teacherCount++; if (segment === "product") c[teacher].productCount++; if (segment === "UNR") c[teacher].unrCount++; return c; }, {})); console.log(result);