Using a data array of numbers returns an array of equilibrium indexes

getEquilibriumIndexes.js

var data = [-1, 3, -4, 5, 1, -6, 2, 1];

function upperTotal(index, data) {
    var totalUpper = 0;
    
    for (var i = index + 1, l = data.length; i < l; i++) {
        totalUpper = totalUpper + data[i];
    }
    
    return totalUpper;
}

function lowerTotal(index, data) {
    var totalLower = 0;
    
    for (var i = 0, l = data.length; i < index; i++) {
        totalLower = totalLower + data[i];
    }
    
    return totalLower;
}

function isEquilibriumIndex(currentIndex, data) {
    var totalLower = lowerTotal(currentIndex, data);
    var totalUpper = upperTotal(currentIndex, data);
    
    return totalLower === totalUpper;
}

function getEquilibriumIndexes(data) {
    var equilibriumIndexes = [];
    for (var i = 0, l = data.length; i < l; i++) {
        if (isEquilibriumIndex(i, data)) {
            equilibriumIndexes.push(i);
        }
    }
    return equilibriumIndexes;
}

console.log(getEquilibriumIndexes(data));