Codility TapeEquilibrium Solution in Javascript - 100% score

TapeEquilibrium.js

/*
A non-empty zero-indexed array A consisting of N integers is given. Array A represents numbers on a tape.

Any integer P, such that 0 < P < N, splits this tape into two non-empty parts: A[0], A[1], ..., A[P − 1] and A[P], A[P + 1], ..., A[N − 1].

The difference between the two parts is the value of: |(A[0] + A[1] + ... + A[P − 1]) − (A[P] + A[P + 1] + ... + A[N − 1])|

In other words, it is the absolute difference between the sum of the first part and the sum of the second part.
*/

function solution(A) {
    var sumRight = A.reduce((pv, cv, idx) => (idx > 0) ? (pv + cv) : (0), 0);
    var sumLeft = 0;
    var substractions = [];
    var maxI = A.length - 1;
    
    for(var i = 0; i < maxI; i += 1){
        sumLeft += A[i];
        substractions.push(Math.abs(sumLeft - sumRight));
        if (i + 1 <= maxI) sumRight -= A[i + 1];
    }
    
    return substractions.reduce((pv, cv, idx) => (idx > 0) ? ((pv < cv)? pv : cv) : (cv), 0);
}

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)
    
    let sum = A.reduce((a, b) => a + b, 0);
    let diff = 0;
    let index = 0;
    
    for(let i=0; i<A.length; i++){
        let d = sum - A[i];
        if(diff < d){
            diff = d;
            index = i;
        }
    }
    
    return index;
}

function solution(A) {
    let prevSum = A[0];
    let nextSum = A.slice(1, A.length).reduce((a, b) => {
        return a + b;
    });
    let min = Math.abs(nextSum - prevSum);
    for (let i = 1; i < A.length - 1; i++) {
        prevSum += A[i];
        nextSum -= A[i];
        if (Math.abs(prevSum - nextSum) < min) {
            min = Math.abs(prevSum - nextSum);
        }
    }
    return min;
}

function solution(A) {
    let leftNum = 0;
    let rightNum = A.reduce((a,b) => a+b);
    let answer = null;
    for (let i=0; i<A.length-1; i++) {
        leftNum += A[i];
        rightNum -= A[i];
        const diff = Math.abs(leftNum - rightNum)
        if (answer === null || answer > diff) {
            answer = diff
        }
    }
    return answer
}

function solution(A) {
    const arr = [...A];
    let solution = Infinity
    let contR = 0;
    let contL = 0
    function sumTotal(arr){
        arr.map(item => {contL += item})
        return contL
    }
    sumTotal(arr)
    for (var i = 0; i < arr.length - 1; i++){
        contR += arr[i]
        contL -= arr[i]
        if(solution > Math.abs(contL - contR)){
            solution = Math.abs(contL - contR)
        }
    }
    return solution
}

function solution(A) {

let sumA = A.reduce((a, b) => a + b, 0)
let sumB = 0
let diff = []
for(let i=0; i<A.length-1; i++){
    sumB += A[i]
    sumA -= A[i]
    diff[i] = Math.abs(sumA-sumB)
}
D = diff.sort((a,b)=>a-b,0)
return D[0];

}

function solution(A) {
    const sum = A.reduce((s, i) => s + i, 0)
    let min = Number.MAX_VALUE
    let half_sum = 0
    for(let i = 0; i < A.length - 1; i++) {
        half_sum += A[i]
        min = Math.min(min, Math.abs(sum - (2 * half_sum)))
    }
    return min
}

function solution(A) {
    const total = A.reduce((acc, number) => acc + number, 0)
    let sum1 = 0;
    let sum2 = total;
    let number;
    
    for (i= 0; i < A.length - 1; i++) {
        sum1 += A[i]
        sum2 -= A[i]
        const value = Math.abs(sum1 - sum2)
        if (number === undefined || value < number) {
            number = value
        }
    }
    
    return number
}

`
function solution(A) {
if (A.length === 2) {
return Math.abs(A[0] - A[1])
}
let lowest = Number.MAX_VALUE

let totalSumRight = A.reduce((s, c, idx)=>s+c, 0)

let totalSumLeft = 0

for (let i = 0; i < A.length-1; i++) {
    totalSumLeft = totalSumLeft + A[i]
    const ltotalSumRight = totalSumRight - totalSumLeft

    const abDiff = Math.abs(totalSumLeft - ltotalSumRight)
    if (abDiff < lowest) {
        lowest = abDiff
    }
}
return lowest

}

`

function solution(A) {
  let sumLeft = A[0];
  let sumRight = A.reduceRight(
    (sum, current, i) => (i === 0 ? sum : sum + current),
    0
  );
  let result = getDiff(sumLeft, sumRight);

  for (let i = 1; i < A.length - 1; i++) {
    const current = A[i];

    sumRight -= current;
    sumLeft += current;

    const diff = getDiff(sumLeft, sumRight);
    result = result > diff ? diff : result;
  }

  return result;
}

function getDiff(num1, num2) {
  return Math.abs(num1 - num2);
}