变量数据在while循环后消失

Question

我从我的API获取数据，如下所示：

function getWeight (username) {
/* This function takes a username as a parameter,
    then it calls the API URL using the username
    so that it gets the weights of that particular
    user.
*/
  var weights;

  $.ajax({
      type: 'GET',
      url: '/weight/api/get_weight_data_admin/'+username,
      dataType: 'json',
      async: false,
      success: function (data) {
        weights = data
      }
    });

  getWeightPlots(weights);
}

当我执行console.log（权重）时，上面的代码按预期工作，它正好显示了我的期望：

问题出在下面的代码中;我在下面的函数中创建的列表，并在while循环中向其追加值，在退出while循环后，我看不到它中的值。

function getWeightPlots (weights) {
/**
 * This function takes a list of dictionaries, which contain
 * dates when the weight was entered and the weight itself.
 * It returns a list of weights that can be used for plotting on
 * the graph.
 */

  var weightList = [];

  // get the last 12 months
  var months = getMonths();

  var numWeights = weights.length;

  var i = 0;
  var y = 0;
  while (y < months.length) {
    var weightMonthNum = weights[i]
    weightMonthNum = weightMonthNum['date']
    weightMonthNum = weightMonthNum.split('-');
    weightMonthNum = parseInt(weightMonthNum[1])

    var monthNum = monthToMonthNum(months[y])

    if (weightMonthNum < monthNum){
      i++;
    }
    else if (weightMonthNum == monthNum) {
      weightList.push(1);
      i++;
      y++;
    }
    else {
      y++;
      weightList.push(0);
    }
  }

  console.log(weightList);
}

我试过调试，一切似乎都运行正常，任何想法？

Answer 1

当调用getWeightPlots时，weights为空（未定义）。等待ajax完成然后在success方法中调用它。