我肯定錯(cuò)過(guò)了什么。在下面的代碼中，我清楚地聲明loopingAdjustment，然后在它下面我在fromCharCode函數(shù)中調(diào)用它。所以，我正在使用它，對(duì)吧？我應(yīng)該可以調(diào)用它，因?yàn)樗谕粋€(gè)范圍內(nèi)，對(duì)吧？為什么 VSCode 說(shuō)它“從未使用過(guò)”，為什么我的終端說(shuō)它“未定義”？謝謝你。const caesar = function(startingString, shiftAmount) {        let itemizedString = startingString.split('');    const mappedLetters = itemizedString.map(stringLetter => {                //turn each letter in array into their respective character code        let thisLetter = stringLetter.charCodeAt(stringLetter);        // checking if character is alphabetic and converting its charcode back to a letter        if (thisLetter < 65 || (thisLetter > 90 && thisLetter < 97) || thisLetter > 122) {            return;        } else {            shiftedLetter = thisLetter + shiftAmount;        }                // making sure the shifted letters loop to beginning, or end, of alphabet        if (thisLetter > 96 && shiftedLetter > 122) {            let loopingAdjustment = shiftedLetter - 26;        } else if (thisLetter > 96 && shiftedLetter < 96) {            let loopingAdjustment = shiftedLetter + 26;        } else if (thisLetter < 91 && shiftedLetter > 90) {            let loopingAdjustment = shiftedLetter - 26;        } else if (thisLetter < 91 && shiftedLetter < 65) {            let loopingAdjustment = shiftedLetter + 26;        } else {            let loopingAdjustment = shiftedLetter;        }        let finalString = String.fromCharCode(loopingAdjustment);        return finalString;    });    console.log(mappedLetters);    return mappedLetters.join('');}module.exports = caesar