javascript - 带有回调和简化错误处理的 Coffeescript

Question

我希望能够从此 coffeescript 代码重构错误处理:

# Do some stuff with 2 levels of asynchronous callbacks and error handling
vote = (res, data) ->
  Case.findOne { caseId: data.id }, (err, mycase) ->
    if err
      console.error 'Vote failed'
    else
      myvote = new Vote
        case: mycase._id
      myvote.save (err) ->
        if err
          console.error 'Could not add vote'
        else
          console.log 'Success!'

像这样:

# Run my function, do error handling, and run the callback if no error
runit = (func, arg, errmsg, callback) ->
  func arg, (err, docs) ->
    if err
      console.log errmsg + ': ' + err
    else
      callback docs

# Original code, simplified
vote = (res, data) ->
  runit Case.findOne { caseId: data.id }, 'Vote failed', (mycase) ->        
      myvote = new Vote
        case: mycase._id
      runit myvote.save, 'Could not add vote', () ->   
          console.log 'Success!'

显然，runit 函数需要能够正确处理一个或多个参数，而我并没有尝试正确编写代码。

如果我这样运行它，我会得到一个错误:

node.js:201
    throw e; // process.nextTick error, or 'error' event on first tick
          ^
TypeError: Cannot read property 'findOne' of undefined
    at /tmp/node_modules/mongoose/node_modules/hooks/hooks.js:27:28
    at /tmp/lib/api.js:227:12
    at Promise.<anonymous> (/tmp/lib/api.js:216:16)
    at Promise.<anonymous> (/tmp/node_modules/mongoose/lib/promise.js:120:8)
    at Promise.<anonymous> (events.js:67:17)
    at Promise.emit (/tmp/node_modules/mongoose/lib/promise.js:59:38)
    at Promise.complete (/tmp/node_modules/mongoose/lib/promise.js:70:20)
    at /tmp/node_modules/mongoose/lib/query.js:885:15
    at model.<anonymous> (/tmp/node_modules/mongoose/lib/document.js:181:5)
    at model.init (/tmp/node_modules/mongoose/lib/model.js:181:36)

Answer 1

# Run my function, do error handling, and run the callback if no error
runit = (func, args..., errmsg, callback) ->
  func args..., (err, docs) ->
    if err
      return console.log errmsg + ': ' + err
    callback docs

# Original code, simplified
vote = (res, data) ->
  runit Case.findOne { caseId: data.id }, 'Vote failed', (mycase) ->        
    myvote = new Vote
      case: mycase._id
    runit myvote.save, 'Could not add vote', ->   
      console.log 'Success!'

runit 编译成什么:

runit = function() {
  var args, callback, errmsg, func, _i;
  func = arguments[0], args = 4 <= arguments.length ? __slice.call(arguments, 1, _i = arguments.length - 2) : (_i = 1, []), errmsg = arguments[_i++], callback = arguments[_i++];
  return func.apply(null, __slice.call(args).concat([function(err, docs) {
    if (err) return console.log(errmsg + ': ' + err);
    return callback(docs);
  }]));
};