For-Of 循环“Set 不是函数”

Question

I have this code here:

function Duplicate(array1, array2){
    var wordSet = new Set();
    var result = [];

    console.log(wordSet)
    for(let letter of array1){
       if(!wordSet(array1[letter])){
           wordSet.add(array1[letter])
       }
    }

    for(let word of wordSet){
        result.push(word)
    }

    return result;
}

console.log(Duplicate(['a','b','c'],['a','k','d','m','k']))

However, when I tried to run it, it says "wordSet is not a function". If I use the regular "for..." loop it would work fine. Does anyone know what the problem here is?

Answer 1

As mentioned in the comment, wordSet is not a function so you can not call it. I think the commenter is right that you are after using has with your set. Sets are unique (you probably already knew that). Sets can be used with for...of loops and de-structured.

for(let word of wordSet) // this is allowable

I am not sure what you are after in this area of the code as you can simply just add each letter of the array to the Set and it will only keep the unique ones with no duplicates. You never use array2 in the function. Are you trying to find the duplicate letters in array1 and array2?

If so you could do the following:

1) load one Set with the each array item by using add (add each letter, the set will only keep the unique ones)

2) using the second array you can search the against the set, something like:

for (let val of array2){ // look at each letter in the array
   if (wordSet.has(val)){ // if that letter is in your unique set from array 1
      result.push(val);  // push it onto your duplicate only array
   } // end if
} // end for

return result; // return the duplicate array to the caller

This whole thing might be more efficient using 2 sets (a set of unique letters for each array). Depends what you are after really.

Hope this helps you along the way. -WWC