Mongoose countDocuments 未按预期返回

Question

I am attempting to write a function to find if a document within a mongoose database exists before submitting a query. However, it keeps saying that the document does not exist, even though it does.

/**
 * Determines if a Journal already exists (via ISSN numer)
 * @param {string} data - The ISSN number of the Journal to be checked
 * @return {boolean} - True = journal exists, false it doesnt exist.
 */
async function getJournalByISSN(data) {
  const issn = String(data);
  const docCount = await Journal.countDocuments().or([
    {issn_electronic: issn},
    {issn_print: issn}]);
  let value = false;
  console.log(docCount, value);
  if (docCount != 0) value = true;
  return value;
}

The console.log of the data given returns a correctly formatted ISSN. When I debug the mongoose query it looks well-formed.

console.log

journals.countDocuments {"$or":[{"issn_electronic":"1234-​1234"},{"issn_print":"1234-1234"}]} {}

When manually specifying the search field, ie

{issn_electronic: '1234-1234'}, {issn_print: '1234-1234'}]}

It returns the correct document count value.

Interestingly copying and pasting the debug of mongoose shows that there has been blank spaces injected into the string

eg

journals.countDocuments {"$or":[{"issn_electronic":"1234- 1234"},{"issn_print":"1234- ​1234"}]} {}

Answer 1

This was an issue with hidden characters

String has hidden characters, Can't able to verify ,

By replacing the data string via it solved the issue

data = data.replace(/[\u200c\u200b]/g, '')