Array manipulations in Javascript

assignment.js

let list = [9,5,5,0,2,5,9,5,6,7];
//find if any of the number is greater than 6
//find the sum of all numbers
//find the number of even numbers and number of odd numbers
//find how many times each number repeats
//find an array where each number is the squares the corresponding number in the first array.
//find an array where the character representing the number repeats the number of times of the corresponding number 
// ex : [2, 3, 1] = ['c','c','d','d','d','b']
var result = list.some(function(element) {
    return element > 10;
})

console.log(`Problem 1 result : ${result}`);

let sum=0;
for (var i=0; i<list.length; i++) {
    sum += list[i];
}
console.log(`Problem 2 Method 1 sum: ${sum}`);

sum=0;
list.forEach((element) => {
    sum+=element;
})

console.log(`Problem 2 Method 2 sum: ${sum}`);

console.log(`Problem 2 Method 3: Sum ${list.reduce((prev, current) => prev+current, 0)}`);

//find the number of even numbers and number of odd numbers
// let evenNumbers = list.filter(function(element) {
//     return element % 2 == 0;
// })

// let oddNumbers = list.filter(function(element) {
//     return element % 2 == 1;
// })

// let differentOddNumbers = oddNumbers.reduce(function(prev, current){
//     if (prev.indexOf(current) == -1) {
//         prev.push(current);
//     }
//     return prev;
// },[]);

let result1 = list.reduce(function(prev, current) {
    if (current % 2 ==0) {
        if (prev.even.indexOf(current) == -1) {
            prev.even.push(current);
        }
    } else {
        if (prev.odd.indexOf(current) == -1) {
            prev.odd.push(current);
        }
    }
    return prev;
}, {
    even : [],
    odd: []
})

console.log(`Problem 3 Odd ${result1.odd}, even ${result1.even}`);

//find an array where each number is the squares the corresponding number in the first array.

var newArray = [];
for(var i=0; i<list.length; i++) {
    newArray.push(list[i] * list[i]);
}

console.log(`Problem 4 ${list.map(function(element) {
    return element * element;
})}`);


list.map(element => element * element)

let x = element => element * element

let y = function(element) {
    return element * element;
}

//find how many times each number repeats
let result3 = list.reduce((prev, element) => {
    if (prev[element]) {
        prev[element] = prev[element] +1;
    } else {
        prev[element] = 1;
    }
    return prev;
},{});

console.log(`Result: ${JSON.stringify(result3)}`);