我认为您正在寻找的是一个对象数组：

// this should be an array
var questions = [];
for (var i = 0; i < tmp_questions.length; i++) {
    // for each iteration, create an object and fill it
    questions[i] = {};
    questions[i]["questions"] = tmp_questions[i];
    questions[i]["input_type_id"] = tmp_question_types[i];
    questions[i]["choices"] = tmp_choices[i];
}

或者像这样清晰地表示：

// this should be an array
var questions = [];
for (var i = 0; i < tmp_questions.length; i++) {
    // for each iteration, push an object like so
    questions.push({
        "questions":     tmp_questions[i],
        "input_type_id": tmp_question_types[i],
        "choices":       tmp_choices[i]
    });
}

您需要先初始化对象。只需写入

questions = [];
for (var i = 0; i < tmp_questions.length; i++) {
    questions[i] = {};
    questions[i]["questions"] = tmp_questions[i];
    questions[i]["input_type_id"] = tmp_question_types[i];
    questions[i]["choices"] = tmp_choices[i];
}

插入前必须初始化。 检查一下

var tmp_choices= tmp_question_types = tmp_questions = [1,2,3,4,5];

var questions = [];  // If you want questions to be array of objects then use []

for (var i = 0; i < tmp_questions.length; i++) {
questions[i] = {};
    questions[i]["questions"] = tmp_questions[i];
    questions[i]["input_type_id"] = tmp_question_types[i];
    questions[i]["choices"] = tmp_choices[i];
}
console.log(questions);