Deep diffing a js-object ignoring arrays

diff_js_object.js

const test1 = {
    k0: 1,
    k1: 1,
    k3: 3,
    k4: {
        c: 4
    },
    k5: {
        c: 2
    }
};

const test2 = {
    k0: 1,
    k2: 1,
    k3: 4,
    k4: {
        c: 3
    },
    k5: 5
};

const test3 = {
    a: {
        a: {
            a: {
                b: 2,
                c: {
                    a: 1
                }
            }
        }
    }
};

const test4 = {
    a: {
        a: {
            a: {
                b: 3,
                d: {
                    c: 1
                }
            }
        }
    }
};

function findCommonKeys(a, b) {
    return Object.keys(a).filter(aKey => b[aKey]);
}

function findUniqueKeys(a, b) {
    return Object.keys(a).filter(aKey => !b[aKey]);
}

function printDiffValue(key, aValue, bValue, prefix) {
    console.log(`Diffing: ${prefix ? `${prefix}.${key}` : key} avalue`, aValue, 'bvalue', bValue);
}

function printUniqueKeys(keys, obj, objectPrefix, prefix) {
    keys.forEach(key => {
        console.log(`${objectPrefix} Unique: ${prefix ? `${prefix}.${key}` : key}`, 'value', obj[key]);
    });
}

function diff(a, b, diffKey = "") {
    
    const aKeys = findUniqueKeys(a,b);
    const bKeys = findUniqueKeys(b,a);
    const commonKeys = findCommonKeys(a,b);
    
    aKeys && printUniqueKeys(aKeys, a, 'a', diffKey);
    bKeys && printUniqueKeys(bKeys, b, 'b', diffKey);
    
    commonKeys.forEach(key => {
        const avalue = a[key];
        const bvalue = b[key];
        
        if (typeof(avalue) === 'object' && typeof(bvalue) === 'object') {
            diff(avalue, bvalue, diffKey ? `${diffKey}.${key}` : key);
        } else if (avalue !== bvalue) {
            printDiffValue(key, avalue, bvalue, diffKey);
        }
    });
}

diff(test1, test2);
console.log('-----')
diff(test1, {});
console.log('-----')
diff({}, test2);
console.log('-----')
diff(test3, test4);
console.log('-----')
diff(test1, test4);
console.log('-----')
diff(test2, test4);
console.log('-----')
diff(test1, test3);
console.log('-----')
diff(test2, test3);