constructor parameters with @ sometime not recognized

[robert-boulanger]

When prefixing constructor arguments with @

like

export class ClassTest
  ###*
   * @constructor
   * @param {object} option
   * @param {Function} callMe
   * @param {string} name
  ###
  constructor: (@option,@callMe, name)->
      ...

Coffeesense complains:

JSDoc '@param' tag has name 'option', but there is no parameter with that name.

The position of this error could not be mapped back to CoffeeScript, sorry. Here's the failing JavaScript context:

    /**
   * @constructor
   * @param {object} option
   * @param {Function} callMe
   * @param {string} name 

JSDoc '@param' tag has name 'callMe', but there is no parameter with that name.

The position of this error could not be mapped back to CoffeeScript, sorry. Here's the failing JavaScript context:

    /**
   * @constructor
   * @param {object} option
   * @param {Function} callMe
   * @param {string} name 

However changing the param name from option to options (in code and jsdoc) let the message disappear for the moment, but it pops up later again complaining about the new names

[phil294]

The example code you gave me gives no error. But I think I found your specific problem anyway: You most likely have another variable in the same scope, also called option (have you? if not, could you share the code?). Perhaps outside the class:

export class ClassTest
  constructor: (@option)->

option = 123

The official CoffeeScript compiler translates this into

var option;

export var ClassTest = class ClassTest {
  constructor(option1) {
    this.option = option1;
  }

};

option = 123;

Notice the option1. Apparently the compiler checks for the existence of a variable of the same name when creating the local constructor variable. In the example above, this does not make sense, but it does when option lives inside the constructor:

export class ClassTest
  constructor: (@option)->
  option = 123

becomes

export var ClassTest = (function() {
  var option;

  class ClassTest {
    constructor(option1) {
      this.option = option1;
    }

  };

  option = 123;

  return ClassTest;

}).call(this);

In this case, if it weren't option1 but option, it would overshadow the global option and thus making this.option = option1 useless.

So, to solve this issue, the CS compiler needs to look for usage the variable in the constructor itself, not the surrounding code. Until now, this was not a problem because who cares what the invisible variable is called. But with JSDoc, it is... I'll create a issue in a sec

It's a bit of an edge case, really. Besides removing the conflicting var from the same scope, there's at least two ways to workaround it:

class ClassTest
  ###*
   * @param {object} option
  ###
  constructor: (option)->
    @option = option

class ClassTest
  constructor: (###* @type {object} option ###)->

In future, with Coffee-Type-Script (there's no name yet), the best way will be

class ClassTest
  constructor: (@option ~ object) ->

but only if you will want to use TS anyway, so a solution to the JSDoc problem is desirable.

[phil294]

You could also change your * @param {object} option to * @param {object} option1 to fix the error, but this is a very bad idea because it will then surely break in the future if you edit the code again

Also, this The position of this error could not be mapped back to CoffeeScript, sorry. Here's the failing JavaScript context: is a bit stupid, it should at least try to go near the actual position, not the start of the file. I'll fix that soon

[robert-boulanger]

You are right, there is an option outside the scope of the class, but not as you assumed :

the complete sample.coffee to reconstruct the problem:

outSideMethod = (s) ->
  option = s

export class ClassTest
  ###*
   * @constructor
   * @param {object} option
   * @param {Function} callMe
   * @param {string} name
  ###
  constructor: (@option,@callMe, name)->
    a = 2

and here the output of the compiler:

var outSideMethod;

outSideMethod = function(s) {
  var option;
  return option = s;
};

export var ClassTest = class ClassTest {
  /**
   * @constructor
   * @param {object} option
   * @param {Function} callMe
   * @param {string} name
   */
  constructor(option1, callMe, name) {
    var a;
    this.option = option1;
    this.callMe = callMe;
    a = 2;
  }

};

and here the output of coffeesense

JSDoc '@param' tag has name 'option', but there is no parameter with that name.

The position of this error could not be mapped back to CoffeeScript, sorry. Here's the failing JavaScript context:

  /**
   * @constructor
   * @param {object} option
   * @param {Function} callMe
   * @param {string} name

[phil294]

yeah that's even worse. there is an issue about this already: jashkenas/coffeescript#4865

The code simply gets a list of all used identifiers in the whole file and then avoids using those for generated variable names. Why? Because it’s simple. Tracking scope is more complicated for no gain. And even if we did that it wouldn’t help if the name is in the same scope.

[robert-boulanger]

Maybe it would be a good idea to collect all those things and add it to the documentation of coffeesense ?

[phil294]

I had added it to the readme last year.

other than that, as there's nothing to do from an extension standpoint, I'll close this