SOURCE

let arr = [1,2,2,3,4,5,5,6,7,7,7,8,9]
function uniqueSet(arr) {
    return [...new Set(arr)]
}
console.log(`uniqueSet:${uniqueSet(arr)}`)

function uniqueSplice(arr) {
    for(let i=0;i<arr.length;i++) {
        for (let j=i+1;j<arr.length;j++) {
            if (arr[i] === arr[j]) {
                arr.splice(j,1)
                j--
            }
        }
    }
    return arr
}
console.log(`uniqueSplice:${uniqueSplice(arr)}`)

function uniqueIncludes(arr) {
    let newArr = []
    for(let i=0;i<arr.length;i++) {
        if (!newArr.incluedes(arr[i])) {
            newArr.push(arr[i])
        }
    }
    return newArr
}
console.log(`uniqueIncludes:${uniqueIncludes(arr)}`)

let