Transforming an array of objects in javascript

problem.txt

[
{"name": "user1", "marks": 10, "gender": "male"},
{"name": "user2", "marks": 12, "gender": "male"},
{"name": "user3", "marks": 15, "gender": "male"},
{"name": "user4", "marks": 20, "gender": "female"},
{"name": "user5", "marks": 25, "gender": "female"},
]

Expected output : 

{
    "10-14": { "male" : 1, "female": 1},
    "15-19": { "male": 1, "female": 0},
    "20-24": { "male": 0, "female": 1},
    "25-29": { "male": 0, "female": 1},
}

1. Marks are always integers.
2. The ranges will depend on the data and they are always continuous.
3. Each range will be of size 5 and start with a multiple of 5.

students.js

//Input data
var students =  [
    { name: "user1", marks: 10, gender: "male" },
    { name: "user2", marks: 12, gender: "male" },
    { name: "user3", marks: 15, gender: "male" },
    { name: "user4", marks: 20, gender: "female" },
    { name: "user5", marks: 25, gender: "female" },
   ];

//Extract the overall range of data
const range = students.reduce((range,student) => {
    return { min : Math.min(range.min, student.marks), 
    max : Math.max(range.max, student.marks)};
    }, { min : students[0].marks, max : students[0].marks });

//Extract the range as multiples of 5
range.min = Math.floor(range.min/5) * 5;
range.max = Math.floor(range.max/5) * 5;

//Construct an array of ranges
const ranges = [];
for(let i = range.min; i<= range.max; i+= 5) {
    ranges.push(i);
}

//Construct a result array.
const result = ranges.map(element => ({ start : element, male : 0, female : 0}));

//Iterate each student and modify the result.
students.forEach(student => {
    const r = result.find(range => student.marks >= range.start && student.marks < range.start + 4);
    r[student.gender]++;
})

//Format the result into output
const output = result.reduce((acc, item) => {
    return {...acc, [`${item.start}-${item.start+4}`] : { male : item.male, female: item.female}}
}, {});

//Print
console.log(output);

// Output:
// { '10-14': { male: 2, female: 0 },
//  '15-19': { male: 1, female: 0 },
//  '20-24': { male: 0, female: 1 },
//  '25-29': { male: 0, female: 1 } }