SOURCE

const arr = [1, 4, 5, 2,7, 3, 7, 7]

const Deduplication=(arr)=> {
    let newarr = []
    arr.map(item => {
        if (!newarr.includes(item)) {
            newarr.push(item)
        }
    })
    return newarr
}
// console.log(Deduplication(arr))
const Deduplication1=(arr)=>{
let newArr=[]
return newArr=[...new Set(arr)]
}
console.log(Deduplication1(arr))
const Deduplication2=(arr)=>{
let newArr=[]
return newArr= arr.filter((item, index, arr) => arr.indexOf(item) === index)
}
console.log(Deduplication2(arr))