在包含数组的数组中查找元素

Question

I have a Questions Array tht has two elements that are Player 1's questions and Player 2's questions. The questions are objects arranged like so:

var tempQuestion = {
    qId: i,
    leftQ: leftQ,
    rightQ: rightQ,
    correctAnswer: correctAnswer,
    allAnswers: sortedAnswers,
    questionText: questionText
}

I want to access the whole question object and pull this out into another array of current questions (one for each player), so both players have the same progress but they don't override each others questions. So I try to pull them out of the array with a find on the ID field (much like you would in a C# or VB MVC application).

for (j = 0; j < playerCount; j++) {
    // Pick a random question
    this.Questions.push(this.players[j].questions);
    var rand = this.Questions[j].length - 1;
    function findQ(q) { 
        return q.qId === rand;
    }
    this.CurrentQuestion[j] = this.Questions[j].find(findQ);
}

However this returns CurrentQuestion as a null value.

Debugging told me that this.Questions is populated, so there's no problem there and the player count is also populated so it's not that either. And the this.CurrentQuestion[j] = this.Questions[j].find(findQ); line is the one that breaks the application with the error:

this.CurrentQuestion is null

Answer 1

The array this.CurrentQuestion must first exist before you can access it's elements

Before you start the loop add:

this.CurrentQuestion=[];