Google Apps Script：如何从含空值的嵌套对象提取raw值

我需要从Yahoo财经API返回的对象中提取所有type键下的raw值。现有代码在type键数据无缺失或空值时运行正常，但当部分type键包含null元素或为空时，会报错：

TypeError: Cannot read properties of null (reading 'reportedValue')

我希望修改代码，实现当type键没有raw值时，数组存入[[type, ''], ....]，并移除所有null元素，请问应该如何修改原代码中的这一行：

var array = obj.timeseries.result.map(o => types.flatMap(type => o[type] ? [type, ...o[type].map(({ reportedValue: { raw } }) => raw)] : []));

完整原代码如下：

function test() {

  var url = 'https://query2.finance.yahoo.com/ws/fundamentals-timeseries/v1/finance/timeseries/CRWD?lang=en-US&region=US&symbol=CRWD&padTimeSeries=true&type=annualTaxProvision,trailingTaxProvision,annualPretaxIncome,trailingPretaxIncome,annualInterestExpenseNonOperating,trailingInterestExpenseNonOperating,annualLongTermDebt,quarterlyLongTermDebt,annualCurrentDebt,quarterlyCurrentDebt,annualCashCashEquivalentsAndShortTermInvestments,quarterlyCashCashEquivalentsAndShortTermInvestments,annualFreeCashFlow,trailingFreeCashFlow&merge=false&period1=493590046&period2=1672980169&corsDomain=finance.yahoo.com'
  
  var obj = UrlFetchApp.fetch(url, { muteHttpExceptions: true }).getContentText();
  obj = JSON.parse(obj);  //Convert strings to object
  var types = obj.timeseries.result.flatMap(({ meta: { type } }) => type);
  var array = obj.timeseries.result.map(o => types.flatMap(type => o[type] ? [type, ...o[type].map(({ reportedValue: { raw } }) => raw)] : []));
  array = Object.keys(array).map(k => [...array[k]]); // Convert object to array
  console.log(array)

}

修改后的代码行及完整代码 #

将原代码中的数组生成行替换为以下代码，同时保留原有逻辑框架：

var array = obj.timeseries.result.map(o => 
  types.flatMap(type => {
    // 处理type键不存在或为空数组的情况
    if (!o[type] || o[type].length === 0) {
      return [type, ''];
    }
    // 过滤null元素并安全提取raw值，无值则返回空字符串
    const rawValues = o[type]
      .filter(item => item !== null) // 移除null元素
      .map(item => item?.reportedValue?.raw || ''); // 避免空对象报错，空值返回''
    return [type, ...rawValues];
  })
);

完整修改后的代码：

function test() {

  var url = 'https://query2.finance.yahoo.com/ws/fundamentals-timeseries/v1/finance/timeseries/CRWD?lang=en-US&region=US&symbol=CRWD&padTimeSeries=true&type=annualTaxProvision,trailingTaxProvision,annualPretaxIncome,trailingPretaxIncome,annualInterestExpenseNonOperating,trailingInterestExpenseNonOperating,annualLongTermDebt,quarterlyLongTermDebt,annualCurrentDebt,quarterlyCurrentDebt,annualCashCashEquivalentsAndShortTermInvestments,quarterlyCashCashEquivalentsAndShortTermInvestments,annualFreeCashFlow,trailingFreeCashFlow&merge=false&period1=493590046&period2=1672980169&corsDomain=finance.yahoo.com'
  
  var obj = UrlFetchApp.fetch(url, { muteHttpExceptions: true }).getContentText();
  obj = JSON.parse(obj);  //Convert strings to object
  var types = obj.timeseries.result.flatMap(({ meta: { type } }) => type);
  var array = obj.timeseries.result.map(o => 
    types.flatMap(type => {
      if (!o[type] || o[type].length === 0) {
        return [type, ''];
      }
      const rawValues = o[type]
        .filter(item => item !== null)
        .map(item => item?.reportedValue?.raw || '');
      return [type, ...rawValues];
    })
  );
  array = Object.keys(array).map(k => [...array[k]]); // Convert object to array
  console.log(array)

}

修改说明 #

1. 空值/缺失处理：判断o[type]是否存在或为空数组，直接返回[type, '']，满足空值时存入空字符串的需求。
2. Null元素过滤：通过filter(item => item !== null)移除数组中的null元素，避免后续处理报错。
3. 安全访问属性：使用可选链操作符?.，避免直接访问null对象的reportedValue属性触发报错；当raw值不存在时，返回空字符串替代。

内容的提问来源于stack exchange，提问作者Newbie