[GitHub] david14142 opened a new issue #120: db.head() can cause UnhandledPromiseRejectionWarning in Node.js even when caught

[GitBox <gi...@apache.org>]

david14142 opened a new issue #120: db.head() can cause UnhandledPromiseRejectionWarning in Node.js even when caught
URL: https://github.com/apache/couchdb-nano/issues/120
 
 
   <!--- Provide a general summary of the issue in the Title above -->
   
   ## Expected Behavior
   <!--- If you're describing a bug, tell us what should happen -->
   <!--- If you're suggesting a change/improvement, tell us how it should work -->
   Catching errors from db.head() calls shouldn't cause warnings:
   
   ```
   .catch((error) => {
       console.log('Error: ' + error.message);
   });
   ```
   Should just write the error to the console.
   
   ## Current Behavior
   <!--- If describing a bug, tell us what happens instead of the expected behavior -->
   <!--- If suggesting a change/improvement, explain the difference from current behavior -->
   Although the error is handled, Node.js still emits an  `UnhandledPromiseRejectionWarning`
   
   ## Possible Solution
   <!--- Not obligatory, but suggest a fix/reason for the bug, -->
   <!--- or ideas how to implement the addition or change -->
   This appears to be because db.head() is wrapping a call to db.relax(), and not handling promise rejections from the db.relax().  Propagating errors to the new Promise (e.g. by adding something like `.catch((err) => {reject(err)})`  ) should allow errors to be handled by the calling code.
   
   ## Steps to Reproduce (for bugs)
   <!--- Provide a link to a live example, or an unambiguous set of steps to -->
   <!--- reproduce this bug. Include code to reproduce, if relevant -->
   
   ```
   db.head('this-is-not-a-valid-id')
     .then((header) => {console.log(header)})
     .catch((error) => {
       console.log('Error: ' + error.message);
     });
   ```
   
   ## Context
   <!--- How has this issue affected you? What are you trying to accomplish? -->
   <!--- Providing context helps us come up with a solution that is most useful in the real world -->
   Currently this just produces a warning message in Node.js. 
   
   ## Your Environment
   <!--- Include as many relevant details about the environment you experienced the bug in -->
   * Version used: 7.0.0
   * Browser Name and version: Node.js 10.9.0
   * Operating System and version (desktop or mobile): macOS 10.13.6 (17G65)
   
   

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