'tag.htm'; break; case 'flag': $pre .= $default_pre .= 'flag.htm'; break; case 'my': $pre .= $default_pre .= 'my.htm'; break; case 'my_password': $pre .= $default_pre .= 'my_password.htm'; break; case 'my_bind': $pre .= $default_pre .= 'my_bind.htm'; break; case 'my_avatar': $pre .= $default_pre .= 'my_avatar.htm'; break; case 'home_article': $pre .= $default_pre .= 'home_article.htm'; break; case 'home_comment': $pre .= $default_pre .= 'home_comment.htm'; break; case 'user': $pre .= $default_pre .= 'user.htm'; break; case 'user_login': $pre .= $default_pre .= 'user_login.htm'; break; case 'user_create': $pre .= $default_pre .= 'user_create.htm'; break; case 'user_resetpw': $pre .= $default_pre .= 'user_resetpw.htm'; break; case 'user_resetpw_complete': $pre .= $default_pre .= 'user_resetpw_complete.htm'; break; case 'user_comment': $pre .= $default_pre .= 'user_comment.htm'; break; case 'single_page': $pre .= $default_pre .= 'single_page.htm'; break; case 'search': $pre .= $default_pre .= 'search.htm'; break; case 'operate_sticky': $pre .= $default_pre .= 'operate_sticky.htm'; break; case 'operate_close': $pre .= $default_pre .= 'operate_close.htm'; break; case 'operate_delete': $pre .= $default_pre .= 'operate_delete.htm'; break; case 'operate_move': $pre .= $default_pre .= 'operate_move.htm'; break; case '404': $pre .= $default_pre .= '404.htm'; break; case 'read_404': $pre .= $default_pre .= 'read_404.htm'; break; case 'list_404': $pre .= $default_pre .= 'list_404.htm'; break; default: $pre .= $default_pre .= theme_mode_pre(); break; } if ($config['theme']) { $conffile = APP_PATH . 'view/template/' . $config['theme'] . '/conf.json'; $json = is_file($conffile) ? xn_json_decode(file_get_contents($conffile)) : array(); } !empty($json['installed']) and $path_file = APP_PATH . 'view/template/' . $config['theme'] . '/htm/' . ($id ? $id . '_' : '') . $pre; (empty($path_file) || !is_file($path_file)) and $path_file = APP_PATH . 'view/template/' . $config['theme'] . '/htm/' . $pre; if (!empty($config['theme_child']) && is_array($config['theme_child'])) { foreach ($config['theme_child'] as $theme) { if (empty($theme) || is_array($theme)) continue; $path_file = APP_PATH . 'view/template/' . $theme . '/htm/' . ($id ? $id . '_' : '') . $pre; !is_file($path_file) and $path_file = APP_PATH . 'view/template/' . $theme . '/htm/' . $pre; } } !is_file($path_file) and $path_file = APP_PATH . ($dir ? 'plugin/' . $dir . '/view/htm/' : 'view/htm/') . $default_pre; return $path_file; } function theme_mode_pre($type = 0) { global $config; $mode = $config['setting']['website_mode']; $pre = ''; if (1 == $mode) { $pre .= 2 == $type ? 'portal_category.htm' : 'portal.htm'; } elseif (2 == $mode) { $pre .= 2 == $type ? 'flat_category.htm' : 'flat.htm'; } else { $pre .= 2 == $type ? 'index_category.htm' : 'index.htm'; } return $pre; } ?>node.js - How to write a function that returns an error in javascript - Stack Overflow
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node.js - How to write a function that returns an error in javascript - Stack Overflow

programmeradmin0浏览0评论

In mongoose.js after every query the functions returns (error, result). I would like to write function of my own that does the same.

I thought the answer was to use promises so I wrote this

  login: (user) ->
    q.Promise (resolve, reject, notify) ->
      console.log resolve
      if _.has(user, 'password')
        dashboard.users.find(user).exec().then (err, results) ->
          if err then reject("Error occurred with the database")
          if results then resolve(results) else reject("User not found")
      else
        reject("A password is required for login")

Auth.login(testuser).then (d) ->
    console.log d, "done"

but after research I found that this is an anti pattern and the code does not work (promise is never resolved/rejected). So now I am not sure what to do.

In mongoose.js after every query the functions returns (error, result). I would like to write function of my own that does the same.

I thought the answer was to use promises so I wrote this

  login: (user) ->
    q.Promise (resolve, reject, notify) ->
      console.log resolve
      if _.has(user, 'password')
        dashboard.users.find(user).exec().then (err, results) ->
          if err then reject("Error occurred with the database")
          if results then resolve(results) else reject("User not found")
      else
        reject("A password is required for login")

Auth.login(testuser).then (d) ->
    console.log d, "done"

but after research I found that this is an anti pattern and the code does not work (promise is never resolved/rejected). So now I am not sure what to do.

Share Improve this question edited Nov 26, 2014 at 6:37 grasshopper asked Nov 26, 2014 at 6:28 grasshoppergrasshopper 9584 gold badges14 silver badges30 bronze badges 5
  • How do you know the promise is never resolved/rejected? I don't see that you're using the actual promise anywhere. Did you mean to return the promise from the login() method? – jfriend00 Commented Nov 26, 2014 at 6:35
  • yes I did I forgot to add that code I'll add it now – grasshopper Commented Nov 26, 2014 at 6:36
  • Like I said, you have to return the promise from the login() method so the callers of login() can use it. – jfriend00 Commented Nov 26, 2014 at 6:38
  • my original code had this but it is still the same result you are saying I should have deferred.promise returned at the end right? – grasshopper Commented Nov 26, 2014 at 6:51
  • Avoid the Promise constructor antipattern! – Bergi Commented Aug 21, 2022 at 14:13
Add a ment  | 

1 Answer 1

Reset to default 2

To return errors from functions as promises, there are generally two ways to produce rejected promises:

  • The reject function of your Promise library
  • Throwing an exception in a then callback or returning a rejected promise from it will reject the resulting promise

This has the same effect as building a promise for an async function that calls its node-style callback with an error argument. Your code would be rewritten to

  login: (user) ->
    if _.has(user, 'password')
      q(dashboard.users.find(user).exec()).then (results) ->
        if results 
          results
        else
          throw new Error("User not found")
      , (err) ->
        throw new Error("Error occurred with the database")
    else
      q.reject("A password is required for login")
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