Weird code for defining `get` method

Hi. I’m creating a library that can be used to write universal code and mount it easily in Express on the server and have it run standalone on the web: uexpress so I’m reading the Express code and I noticed that the way the get function (that returns the application settings) is defined is (imho) really weird.

First of all, it seems the actual code for Application.get is in the set function:

app.set = function set(setting, val) {
  if (arguments.length === 1) {
    // app.get(setting)
    return this.settings[setting];
  }

  // ....

application.js#L354

And then later the actual Application.get method is created as an exception in the code that generates the convenience functions for the HTTP methods:

methods.forEach(function(method){
  app[method] = function(path){
    if (method === 'get' && arguments.length === 1) {
      // app.get(setting)
      return this.set(path);
    }

    // ...
  };
});

application.js#L473

Can anyone explain why it is done this way? Or is this just for historical / back. compat reasons?

[dougwilson]

Hi everyone, I know the issue is already closed, but I just wanted to see if I could shed some more light. I can’t really explain the exact history on it, as the changes were made before I became deeply involved, but I can explain what it is at least doing.

See, some time long ago, app.set(name, value) was the way to set a setting to a value and app.get(name) was the way to get a setting value. The problem is that app.get is also the method for creating a GET route, which leads to a weird duel-use method. Back in the PR referenced above, the idea was to move that getting behavior into app.set as app.set(name), with the understanding that set was now a shortened word for “setting”, not “set” as in to set something. For back-compat app.get(name) still lives on, and has not really been revisited since there was talk right after 4.0 that perhaps they should both be moved to app.settings.get and app.settings.set or similar.

[Download]

@dougwilson Thanks for clarifying!