javascript - 在异步函数内调用异步函数时发生事务完成错误

Question

我有以下异步函数来复制名为“调查问卷”的 postgres 数据库表中的记录:

const duplicateQuestionnaire = async(trx, originalQuestionnaireId) => {
  const originalQuestionnaire = await trx
    .select("*")
    .from("Questionnaires")
    .where({
      id: originalQuestionnaireId
    })
    .then(head);

  const newQuestionnaireId = await trx
    .table("Questionnaires")
    .insert(omit(originalQuestionnaire, "id"))
    .returning("id")
    .then(head);

  const sectionIDs = await trx
    .select("id")
    .from("Sections")
    .where({
      QuestionnaireId: originalQuestionnaireId
    });

  sectionIDs.map(element => {
    duplicateSection(trx, element.id, newQuestionnaireId);
  });

  return trx
    .select("*")
    .from("Questionnaires")
    .where({
      id: newQuestionnaireId
    })
    .then(head);
};

复制后，它将调用第二个异步函数来复制名为“Sections”的表中的记录:

const duplicateSection = async (trx, sectionId, newQuestionnaireId) => {
  const originalSection = await trx
    .select("*")
    .from("Sections")
    .where({ id: sectionId })
    .then(head);

  const newSection = omit(originalSection, "id");

  newQuestionnaireId ? (newSection.QuestionnaireId = newQuestionnaireId) : null;

  const newSectionId = await trx
    .table("Sections")
    .insert(newSection)
    .returning("id")
    .then(head);

  return trx
    .select("*")
    .from("Sections")
    .where({ id: newSectionId })
    .then(head);
};

These functions are designed with a hierarchy in mind: duplicateQuestionnaire calls duplicateSection as a questionnaire contains sections. The latter function can be called without calling the former initially and does not call it as part of its actions.

The return value of each function is used as a GraphQL return.

这些函数都对数据库产生了预期的效果；他们工作。但是，duplicateQuestionnaire 正在标记此错误:

(node:172) UnhandledPromiseRejectionWarning: Error: Transaction query already complete, run with DEBUG=knex:tx for more info
web_1  |     at completedError (/app/node_modules/knex/lib/transaction.js:303:9)
web_1  |     at /app/node_modules/knex/lib/transaction.js:277:22
web_1  | From previous event:
web_1  |     at Client_PG.trxClient.query (/app/node_modules/knex/lib/transaction.js:275:34)
web_1  |     at Runner.<anonymous> (/app/node_modules/knex/lib/runner.js:155:36)
web_1  | From previous event:
web_1  |     at /app/node_modules/knex/lib/runner.js:61:21
web_1  |     at runCallback (timers.js:810:20)
web_1  |     at tryOnImmediate (timers.js:768:5)
web_1  |     at processImmediate [as _immediateCallback] (timers.js:745:5)
web_1  | From previous event:
web_1  |     at Runner.run (/app/node_modules/knex/lib/runner.js:47:31)
web_1  |     at Builder.Target.then (/app/node_modules/knex/lib/interface.js:39:43)
web_1  |     at duplicateSection (/app/repositories/DuplicateRepository.js:49:6)
web_1  |     at <anonymous>
web_1  | (node:172) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
web_1  | (node:172) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

我知道问题在于我如何处理 .map() 中的每个 duplicateSection 调用，但是经过一些研究和大量的谷歌搜索，我仍然正在努力解决这个问题。

Answer 1

您想要等待由duplicateSections返回的所有 promise :

 await Promise.all(sectionIDs.map(element =>
    duplicateSection(trx, element.id, newQuestionnaireId)
 ));

这不仅可以确保在运行最终查询之前复制所有部分，还可以链接被拒绝的 promise 。