過濾數組並保留對原始數組索引的引用？

Question

我試圖過濾不正確答案的答案數組，然後只從原始數組中刪除其中的兩個。

代碼：

var answers = [ 
    {text: "foo", isCorrect: false}, 
    {text: "bar", isCorrect: true}, 
    {text: "foo2", isCorrect: false}, 
    {text: "bar2", isCorrect: false} 
] 
var inCorrect = answers.filter((v, i) => !v.isCorrect); 

選擇從inCorrect陣列兩個隨機答案，並得到了答案，數組的索引。

Answer 1

要選擇有兩個隨機不正確的答案沿着正確的答案，你可以使用下面的代碼。這會使原始數組保持不變，並返回對原始數組中對象的引用。

var answers = [ 
 
    {answer: "foo", isCorrect: false}, 
 
    {answer: "bar", isCorrect: true}, 
 
    {answer: "foo2", isCorrect: false}, 
 
    {answer: "bar2", isCorrect: false} 
 
] 
 
function getRandom (ceiling) { 
 
    return Math.floor(Math.random() * (ceiling || 1)); 
 
} 
 
function fiftyFifty (answers) { 
 
    var correct = answers.find(answer => answer.isCorrect); 
 
    var incorrectAnswers = answers.filter(answer => !answer.isCorrect); 
 
    // grab n answers unless there are less than n incorrect answers to choose from 
 
    var numberOfIncorrects = Math.min(2, incorrectAnswers.length); 
 
    var incorrectsToUse = []; 
 
    for (var i = 0; i < numberOfIncorrects; i++) { 
 
     let randomIndex = getRandom(incorrectAnswers.length); 
 
     // splice elem out of array so it doesn't get randomly selected twice 
 
     incorrectsToUse.push(incorrectAnswers.splice(randomIndex, 1)[0]); 
 
    } 
 
    return [correct].concat(incorrectsToUse); 
 
} 
 

 
console.log(fiftyFifty(answers)); 
 
console.log(fiftyFifty(answers)); 
 
console.log(fiftyFifty(answers));

Answer 2

是不是隻分配回answers工作？

var answers = [ 
 
    {val : "foo", isCorrect: false}, 
 
    {val : "bar", isCorrect: true}, 
 
    {val : "foo2", isCorrect: false}, 
 
    {val : "bar2", isCorrect: false} 
 
]; 
 
answers = answers.filter(v => v.isCorrect); 
 

 
console.log(answers);