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node.jsmorgan

morgan.format is not a function when I study the logger middleware

Hi I am learning the source code about morgan

when I saw the line morgan.format('combined', ...) for my understand, why it can run success and not cause morgan.format is not a function. when I extract the main code run in my local and I got the error. how this place is implemented?

can anybody tell me ? thanks in advance.

Solution

  • Thanks to the module.exports magic that makes the format() method accessible to the main morgan() function.

    Here is a minimal reproduction:

    module.exports = morgan
module.exports.format = format  // format() method is now available to morgan

function morgan() {}

morgan.format()  // Hello from format()

function format() {
  console.log('Hello from format()')
}

    In short, module.exports.some_method = some_method add the some_method() function to the main module.