Javascript 为什么我的 JS 递归函数返回一个填充了相同条目的列表

我在学校一直在学习Python，我在自己的时间学习Javascript，并处理一些JS项目.我不明白为什么我的递归函数只是一个具有相同条目的列表.我已经智穷了.如有任何见解，将不胜感激！

功能描述:

示例数据:

const dummyObject1 = {
    'courseCode': 'BLUE',
    'possibleCombos': [1, 2, 3, 4, 5]
}

const dummyObject2 = {
    'courseCode': 'RED',
    'possibleCombos': [11, 22, 33, 44]
}

const dummyObject3 = {
    'courseCode': 'PURPLE',
    'possibleCombos': [111, 222, 333, 444, 555, 666]
}

const dummyList = [dummyObject1, dummyObject2, dummyObject3]``` 

理想情况下，我想要:

let dummySchedules = recursionFunction(dummyList, {})
console.log(dummySchedules)

//ideal console output
[
{'BLUE': 1, 'RED': 11, 'PURPLE': 111},
{'BLUE': 1, 'RED': 11, 'PURPLE': 222},
{'BLUE': 1, 'RED': 11, 'PURPLE': 333},
... //and so on.
]

然而，我得到的列表输出只是同一对象的120个条目.

这是我的代码:

function recursiveFunction(listOfCourses, dictSoFar) {
    //base case, checks if listOfCourses is empty
    if (!listOfCourses.length) {
        return [dictSoFar]
    } else {
        //recursive step

        var arraySoFar = [] //accumulator

        //iterate through each element of listOfCourses[0]['possibleCombos']
        for (let combo of listOfCourses[0]['possibleCombos']) {
            //update dictSoFar entry.
            dictSoFar[listOfCourses[0]['courseCode']] = combo
            
            //filter out the course we just entered into dictSoFar.
            let course = listOfCourses[0]
            var cloneListOfCourses = listOfCourses.filter(item => item !== course)
            
            //recursive call, this time with the filtered out list. If we keep following the
            //the recursive call down, it should reach the point where listOfCourses is empty,
            //triggering the base case. At that point, dictSoFar already has all course: combo 
            //pairs. This should traverse through all possible course: combo pairs.
            var result = recursiveFunction(cloneListOfCourses, dictSoFar)
            
            //update the accumulator
            arraySoFar.push(...result)
        }
        return arraySoFar;
    }
}

发生了什么事？从理论上讲，我认为这种逻辑是有道理的，我也说不出哪里出了问题.