如何强制Promise抛出指定自定义错误并传递至Promise.all的catch？

Got it, let's break down why your Promise.all isn't picking up those custom errors, and how to fix the writeAttachedCMinfo function properly.

The Core Problem #

Right now, when you hit a failed condition (like CM amount > invoice amount), you're doing return new Error('CMisbiggerThanInvoice') — but this doesn't reject the parent Promise. Those return statements are inside nested then callbacks, not in the top-level executor function of your Promise. Returning an Error object here just passes it to the next then in the chain, not the catch handler of your outer Promise.

Step-by-Step Fixes #

Let's rewrite the writeAttachedCMinfo function to properly reject on failed conditions, and clean up the Promise chaining to avoid nested callbacks (which makes error handling way easier):

server.writeAttachedCMinfo = function (invId, cmid) {
  return new Promise(function (resolve, reject) {
    console.log("writeAttachedCMinfo");
    console.log("invoiceId " + invId);
    console.log("cmid " + cmid);

    // Clean up ID strings (simplified)
    const invIdString = JSON.stringify(invId).slice(1, -1);
    const cmIdString = JSON.stringify(cmid).slice(1, -1);
    const projection = 'gwCode certifiedInvoiceAmount buyerReference supplierReference invoiceNo invoiceSerialNo invoiceFiles creditMemos';

    // Use chained Promises instead of nesting for clearer flow
    ubiqInvoice.findById(invIdString, projection)
      .then(function (dbInvoice) {
        const intInvCertifiedAmount = parseInt(dbInvoice.certifiedInvoiceAmount);
        // Return the next Promise to continue the chain
        return creditMemo.findById(cmIdString).then(function (dbCreditMemo) {
          return { dbInvoice, dbCreditMemo, intInvCertifiedAmount };
        });
      })
      .then(function ({ dbInvoice, dbCreditMemo, intInvCertifiedAmount }) {
        const intCreditMemoAmount = parseInt(dbCreditMemo.creditMemoAmount);

        // Check conditions and REJECT explicitly if they fail
        if (intInvCertifiedAmount <= intCreditMemoAmount) {
          console.log('cm bigger than invoice');
          reject(new Error('CMisbiggerThanInvoice'));
          return; // Exit early to avoid unnecessary execution
        }

        if (dbCreditMemo.isAssociated) {
          reject(new Error('CMisAssociated'));
          return;
        }

        const validGwCodes = ["100000000000", "110000000000", "111200000000", "111100000000", "111110000000"];
        if (!validGwCodes.includes(dbInvoice.gwCode)) {
          reject(new Error('wrongggwcode'));
          return;
        }

        // If all checks pass, perform the database updates
        const creditMemoEntry = {
          id: guid.create().value,
          batchId: dbCreditMemo.batchId,
          invoiceId: dbInvoice._id,
          recordTypeCode: "CM",
          buyerReference: dbInvoice.buyerReference,
          supplierReference: dbInvoice.supplierReference,
          creditMemoNo: dbCreditMemo.creditMemoNo,
          creditMemoIssuingDate: dbCreditMemo.creditMemoIssuingDate,
          creditMemoEffectiveDate: dbCreditMemo.creditMemoEffectiveDate,
          lastModificationDate: dbCreditMemo.lastModificationDate,
          currencyCode: dbCreditMemo.currencyCode,
          creditMemoAmount: dbCreditMemo.creditMemoAmount,
          hashCode: dbCreditMemo.hashCode,
          description: dbCreditMemo.description,
          uploadDate: dbCreditMemo.uploadDate,
          isAssociated: true,
        };

        dbInvoice.creditMemos.push(creditMemoEntry);
        dbInvoice.certifiedInvoiceAmount = dbInvoice.certifiedInvoiceAmount - dbCreditMemo.creditMemoAmount;
        
        // Wait for both saves to complete before resolving
        return Promise.all([dbInvoice.save(), dbCreditMemo.save()])
          .then(() => resolve(dbInvoice));
      })
      // Catch all internal errors (queries, saves, etc.) and pass to outer Promise
      .catch(function (error) {
        console.log("error: " + error);
        reject(error);
      });
  });
};

Key Changes Explained #

1. Explicit reject() calls: Every failed condition now triggers reject(new Error('your-error-message')) — this forces the Promise into a rejected state, which will be picked up by your Promise.all catch handler.
2. Chained Promises: Replaced nested then callbacks with a linear chain, making error propagation consistent and the code easier to read.
3. Internal error handling: Added a top-level catch in the Promise chain to catch any errors from database queries or saves, ensuring they don't get swallowed.
4. Wait for all saves: Used Promise.all for the two database save operations to ensure both complete successfully before resolving the outer Promise.

Your Updated Promise.all Call #

Your existing Promise.all code works fine once the writeAttachedCMinfo function is fixed. You can tweak the catch handler to use the error message for cleaner output:

Promise.all(receivedObjs.arrayCMsIds.map(cmid => server.writeAttachedCMinfo(invId, cmid)))
  .then(function (results) {
    return res.json(apiHelp.success(results, "success"));
  }).catch(function (error) {
    res.json(apiHelp.error(error.message, error.message));
  });

Final Notes #

• Rule of thumb: In Promise-based code, returning an Error doesn't reject the Promise — you have to explicitly call reject().
• Avoid deep nesting of then callbacks; chaining them keeps error handling predictable.
• Always catch errors from all async operations (like database calls) to prevent silent failures.

内容的提问来源于stack exchange，提问作者user9601534