12. Substring Count

function countSubstringOccur(value) {
    var keyword = value[0];
    var text = value[1];

    var index = 0,
        count = 0;

    while(true) {
        var nextIndex = value.indexOf(keyword, index);
        if (nextIndex !== -1) {
            index = index + 1;
            count += 1;
        }
        else {
            break;
        }
    }

    return count;
}

console.log(countSubstringOccur(['in', "We are living in a yellow submarine. We don't have anything else. Inside the submarine is very tight. So we are drinking all the day. We will move out of it in 5 days."]));