Question

有以下代码：

  User.prototype.convertFromPermissionsToScopes = ->
    this.scopes = {}
    scopesNames = ['create', 'delete', 'update', 'show']
    for groupName of this.permissions
      this.scopes[groupName] = {}
      scopesNames.forEach (scopeName) ->
        this.scopes[groupName][scopeName] = this.permissions[groupName].indexOf(scopeName) isnt -1

我在最后一行收到错误'this.scopes is undefined'。我该如何解决？谢谢！

Answer 1

使用fat arrow将外部this传递到forEach的上下文：

scopesNames.forEach (scopeName) =>

这将确保将外部范围传递给方法的上下文。

您可以使用:: prototype和@ this旁边的旁注：

User::convertFromPermissionsToScopes = ->
  @scopes = {}
  scopesNames = ['create', 'delete', 'update', 'show']
  for groupName of @permissions
    @scopes[groupName] = {}
    scopesNames.forEach (scopeName) =>
      @scopes[groupName][scopeName] = @permissions[groupName].indexOf(scopeName) isnt -1

foreach循环，在CoffeeScript中链接到'this'

1 个答案: