Coffeescript 匿名函数用作回调函数，但定义的函数不用作回调函数

我有一个模块，如下所示：

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Use a class so that => does what you're expecting it to do
class AtomMarkdownLabels
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  # you may or may not need => here
  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Export an instance of your class
module.exports = new AtomMarkdownLabels

# Just plain old functions so define them that way
process_yaml = (err, data) ->
  console.log "process_yaml is called"

file_changed_added = (file_path) ->
  fs.readFile file_path, 'utf-8', process_yaml
  console.log 'file changed'

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: file_changed_added

# Explicitly name your object rather than using @
module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) ->
    fs.readFile file_path, 'utf-8', AtomMarkdownLabels.process_yaml
    console.log 'file changed'

  process_yaml: (err, data) ->
    console.log "process_yaml is called"

我知道从其他函数调用了

file\u changed\u added

，我在控制台中看到了“file changed”输出，但是如果我将

file\u changed\u added

更改为

file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', (err, data) =>
      console.log "test"
    console.log 'file changed'

---

我看到“测试”和“文件更改”都被正确调用。会发生什么事

=>

有两个稍微不同的用途：

定义命名函数（

f==>…

）或匿名函数

f（x，=>…）

）时，

=>

只需确保函数内部的

@

与周围上下文中的

@

相同

在类中定义方法时：

class C
  m: => ...

=>

确保

@

内部的

m

将是

C

的实例

这两种用法都在创建绑定函数，但它们绑定到不同的对象

您正在使用此结构：

obj =
  func: =>
    # ...

这相当于：

f = =>
  # ...
obj =
  func: f

因为您使用的是普通的旧对象，而不是类。那么，在您的

AtomMarkdownLabels

定义之外的

@

是什么

@

不会有任何用处，特别是，它不会是您的

AtomMarkdownLabels

对象，也不会有

process\u yaml

属性，因此

@process\u yaml

中添加的

文件将是
未定义的
或错误

我不确定Atom具体希望您返回什么，但类应该可以工作，如下所示：

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Use a class so that => does what you're expecting it to do
class AtomMarkdownLabels
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  # you may or may not need => here
  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Export an instance of your class
module.exports = new AtomMarkdownLabels

# Just plain old functions so define them that way
process_yaml = (err, data) ->
  console.log "process_yaml is called"

file_changed_added = (file_path) ->
  fs.readFile file_path, 'utf-8', process_yaml
  console.log 'file changed'

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: file_changed_added

# Explicitly name your object rather than using @
module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) ->
    fs.readFile file_path, 'utf-8', AtomMarkdownLabels.process_yaml
    console.log 'file changed'

  process_yaml: (err, data) ->
    console.log "process_yaml is called"

如果您想要或必须使用普通对象，则可以完全绕过
@
，如下操作：

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Use a class so that => does what you're expecting it to do
class AtomMarkdownLabels
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  # you may or may not need => here
  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Export an instance of your class
module.exports = new AtomMarkdownLabels

# Just plain old functions so define them that way
process_yaml = (err, data) ->
  console.log "process_yaml is called"

file_changed_added = (file_path) ->
  fs.readFile file_path, 'utf-8', process_yaml
  console.log 'file changed'

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: file_changed_added

# Explicitly name your object rather than using @
module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) ->
    fs.readFile file_path, 'utf-8', AtomMarkdownLabels.process_yaml
    console.log 'file changed'

  process_yaml: (err, data) ->
    console.log "process_yaml is called"

或者像这样：

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Use a class so that => does what you're expecting it to do
class AtomMarkdownLabels
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  # you may or may not need => here
  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Export an instance of your class
module.exports = new AtomMarkdownLabels

# Just plain old functions so define them that way
process_yaml = (err, data) ->
  console.log "process_yaml is called"

file_changed_added = (file_path) ->
  fs.readFile file_path, 'utf-8', process_yaml
  console.log 'file changed'

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: file_changed_added

# Explicitly name your object rather than using @
module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) ->
    fs.readFile file_path, 'utf-8', AtomMarkdownLabels.process_yaml
    console.log 'file changed'

  process_yaml: (err, data) ->
    console.log "process_yaml is called"


这也可以解决几天前的咖啡脚本问题。
=>
有两个稍微不同的用途：

定义命名函数（
f==>…
）或匿名函数
f（x，=>…）
）时，
=>
只需确保函数内部的
@
与周围上下文中的
@
相同

在类中定义方法时：

class C
  m: => ...

=>
确保
@
内部的
m
将是
C
的实例

这两种用法都在创建绑定函数，但它们绑定到不同的对象

您正在使用此结构：

obj =
  func: =>
    # ...

这相当于：

f = =>
  # ...
obj =
  func: f

因为您使用的是普通的旧对象，而不是类。那么，在您的
AtomMarkdownLabels
定义之外的
@
是什么
@
不会有任何用处，特别是，它不会是您的
AtomMarkdownLabels
对象，也不会有
process\u yaml
属性，因此
@process\u yaml
中添加的
文件将是
未定义的
或错误

我不确定Atom具体希望您返回什么，但类应该可以工作，如下所示：

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Use a class so that => does what you're expecting it to do
class AtomMarkdownLabels
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  # you may or may not need => here
  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Export an instance of your class
module.exports = new AtomMarkdownLabels

# Just plain old functions so define them that way
process_yaml = (err, data) ->
  console.log "process_yaml is called"

file_changed_added = (file_path) ->
  fs.readFile file_path, 'utf-8', process_yaml
  console.log 'file changed'

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: file_changed_added

# Explicitly name your object rather than using @
module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) ->
    fs.readFile file_path, 'utf-8', AtomMarkdownLabels.process_yaml
    console.log 'file changed'

  process_yaml: (err, data) ->
    console.log "process_yaml is called"

如果您想要或必须使用普通对象，则可以完全绕过
@
，如下操作：

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Use a class so that => does what you're expecting it to do
class AtomMarkdownLabels
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  # you may or may not need => here
  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Export an instance of your class
module.exports = new AtomMarkdownLabels

# Just plain old functions so define them that way
process_yaml = (err, data) ->
  console.log "process_yaml is called"

file_changed_added = (file_path) ->
  fs.readFile file_path, 'utf-8', process_yaml
  console.log 'file changed'

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: file_changed_added

# Explicitly name your object rather than using @
module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) ->
    fs.readFile file_path, 'utf-8', AtomMarkdownLabels.process_yaml
    console.log 'file changed'

  process_yaml: (err, data) ->
    console.log "process_yaml is called"

或者像这样：

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Use a class so that => does what you're expecting it to do
class AtomMarkdownLabels
  # other stuff here

  file_changed_added: (file_path) =>
    fs.readFile file_path, 'utf-8', @process_yaml
    console.log 'file changed'

  # you may or may not need => here
  process_yaml: (err, data) =>
    console.log "process_yaml is called"

# Export an instance of your class
module.exports = new AtomMarkdownLabels

# Just plain old functions so define them that way
process_yaml = (err, data) ->
  console.log "process_yaml is called"

file_changed_added = (file_path) ->
  fs.readFile file_path, 'utf-8', process_yaml
  console.log 'file changed'

module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: file_changed_added

# Explicitly name your object rather than using @
module.exports = AtomMarkdownLabels =
  # other stuff here

  file_changed_added: (file_path) ->
    fs.readFile file_path, 'utf-8', AtomMarkdownLabels.process_yaml
    console.log 'file changed'

  process_yaml: (err, data) ->
    console.log "process_yaml is called"


这也可以解决几天前的咖啡脚本问题。
谢谢您的详细解释。我相信你是对的，这就是我之前遇到的问题的原因。谢谢你的详细解释。我相信你是对的，这就是我之前遇到的问题的原因。