Check any two object in an array are Equal using multiple Conditions

Question

In my angular project i have a DataSource like

  [
    {id: "1", name: "John", age: "23", gender:"M", Role: "Student"},
    {id: "2", name: "Smith", age: "24", gender:"M", Role: "Teacher"},
    {id: "3", name: "Jeff", age: "23", gender:"M", Role: "Student"},
    {id: "4", name: "Ronald", age: "25", gender:"M", Role: "Teacher"},
    {id: "5", name: "Ronak", age: "23", gender:"M", Role: "Student"}
]

I need to check if any two or more lines of data are same or not based on multiple conditions. Eg : If any two lines have same age and gender and Role then return their Names

So the Expected Output will be

[John,Jeff, Ronak]

Since they share the same age, gender and Role else

[]

I tried to group the array, but I didn't find any solution to group it using multiple conditions, then tried nested loops, but seems inefficient and the results were not as expected.

Answer 1

You could take a joined key for the wanted properties, collenct the names for the group and return all names who are in a group with three or more items.

var data = [{ id: "1", name: "John", age: "23", gender: "M", Role: "Student" }, { id: "2", name: "Smith", age: "24", gender: "M", Role: "Teacher" }, { id: "3",  name: "Jeff", age: "23", gender: "M", Role: "Student" }, { id: "4", name: "Ronald", age: "25", gender: "M", Role: "Teacher" }, { id: "5", name: "Ronak", age: "23", gender: "M", Role: "Student" }],
    keys = ['age', 'gender', 'Role'],
    groups = data.reduce((r, o) => {
        const key = keys.map(k => o[k]).join('|');
        r[key] = r[key] || [];
        r[key].push(o.name);
        return r;
    } , {}),
    result = Object.values(groups).flatMap(a => a.length >= 3 ? a : []);

console.log(result);
console.log(groups);