Javascript: Find Peak timestamp in array of min-max timestamp values

findPeak.js

function findPeak(arr) {
    const peaks = []
    let num = 0
    let occur = 0

    arr.forEach(item => {
        for (let i = item.min; i < item.max; i++) {
            peaks.push(i)
        }
    })

    let hashMap = peaks.reduce((acc, value) => {
        acc[value] = acc[value] ? acc[value] + 1 : 1
        return acc
    }, {})


    Object.keys(hashMap).forEach(item => {
        if (hashMap[item] > occur) {
            occur = hashMap[item]
            num = item
        }
    })

    return +num
    
}