just to add something to the thread, when you are in a file "this" is
equals to "exports"
you can try it as:
echo "console.log(this === exports)" | node
2012/7/7 Angel Java Lopez <ajlopez2...@gmail.com>
> Thanks!
>
> I usually do in your suggested way, and I'm with you. But in this special
> case, I feel the user of my module could find a bit weird to write
>
> var st = require('simpletags');
>
> st.html(st.head(st.title('...')), st.body(st.h1(....))
>
> instead
>
> html(head(title('....')), body(h1('...'))
>
> in a controlled way (only in its own module). I want to give him/her an
> option. Ruby has it (as an option, too). It's the first time I found I
> needed it in Node.js. Usually, I assert "Ruby ceremony > Javascript/Node.js
> ceremony", but now, I was trapped by this issue.
>
> My best solutions:
>
> a)
> var st = require(...); // and use with st.h1, st.h2...
>
> b)
> require('simpletags').exportsTo(global); // maybe in browser I could
> export to windows directly in the module
>
> c)
> var simpletags = require('simpletags');
> eval(simpletags.exportLocalCode()); // where .exportLocalCode returns a
> String with "var h1 = simpletags.h1; ... "
> c2)
> var st = require('simpletags');
> eval(st.exportLocalCode('st')); // the local variable name 'st' should be
> informed to be used in var ...= .... string result
>
> On Sat, Jul 7, 2012 at 10:38 AM, Mariusz Nowak <mari...@medikoo.com>wrote:
>
>> In modules you can achieve the same by assigning function to global: e.g.
>> `global.foo = function () { .. }` it will work same as `this.foo = function
>> () { ... }` in REPL. but I would strongly discourage this, relying on
>> global scope is bad practice.
>>
>> I'd say that unless you're using regular require/export logic to share
>> objects between modules, you're doing something wrong. Try to think just
>> with require/exports and then you should quickly find way home. See how
>> module relations in other packages work.
>>
>> --
>> Mariusz Nowak
>> https://github.com/medikoo
>> http://twitter.com/medikoo
>>
>>
>> On Saturday, July 7, 2012 3:18:51 PM UTC+2, ajlopez wrote:
>>>
>>> Thanks for the suggestion!.... but... I missing some part of your
>>> answer.
>>>
>>> I guess I understand the difference btw global, this.property, and var
>>> local. And then, I understand why it not works. What I don't understand is
>>> how to circumvent/solve the problem. I don't know if your answer is:
>>>
>>> a- " you'll get the answers :) " and then, you will know that it's
>>> impossible to solve, or too weird
>>> b- you'll get the answers :) " and it's possible in this (simple)
>>> way.....etc...
>>>
>>> AFAIK, it's "a". Am I right?
>>>
>>> My problem is:
>>>
>>> - module1 requires module2
>>> - I want to use the exposed functions of module2 as they were defined in
>>> module1, using dynamic names. That is, it's not a solution
>>>
>>> var module2 = require('module2');
>>> var Function2 = module2.Function2;
>>>
>>> Usually, I did a bit of experiment at REPL. I found that this works:
>>>
>>> var name = 'Function2';
>>> this[name] = ...
>>>
>>> var obj = new Function2(); // without using this
>>>
>>> BUT it's only works at REPL. So, encouraged by this discovery (I
>>> expected it will not work), I hoped to make it works in other context.
>>>
>>> Now, I understand why it is work in REPL. Notably, in REPL
>>>
>>> this == global
>>>
>>> so it's possible to emulate
>>>
>>> var foo = ...
>>>
>>> with something like (pseudocode)
>>>
>>> name = 'foo'
>>> var [name] = .....
>>>
>>> writing
>>>
>>> name = 'foo';
>>> this[name] = ...
>>>
>>> and then foo is available "as if it is" a local var.
>>>
>>> But inside a running .js, this is not equal to global. I was tricked by
>>> REPL ;-)
>>>
>>> So, the better solution I found so far is to put something like this in
>>> module1:
>>> // http://stackoverflow.com/**questions/5625569/include-**
>>> external-js-file-in-node-js-**app<http://stackoverflow.com/questions/5625569/include-external-js-file-in-node-js-app>
>>>
>>> var fs = require('fs');
>>> var vm = require('vm');
>>>
>>> var includeInThisContext = function(path) {
>>> var code = fs.readFileSync(path);
>>> vm.runInThisContext(code, path);
>>> }.bind(this);
>>>
>>> includeInThisContext(__dirname + '/module2.js');
>>>
>>> console.log(foo); // it's defined
>>>
>>> where module2 define foo:
>>>
>>> foo = {};
>>>
>>> BUT IN MY CASE, module2 doesn't define the functions at its own context:
>>> https://github.com/ajlopez/**SimpleTags/blob/master/lib/**simpletags.js<https://github.com/ajlopez/SimpleTags/blob/master/lib/simpletags.js>
>>> it uses an array to dynamically define and export functions. I never
>>> have
>>>
>>> function h1() {
>>> }
>>>
>>> function h2() {
>>> }
>>>
>>> defined at module2 context. And I don't want this. My DSL defines a
>>> function for each HTML tag.
>>>
>>> Now, I want to have these dynamically defined functions from
>>> module2 accessible in outer module1, as they were local to it.
>>>
>>> I could write inside my module,
>>>
>>> var h1 = makeTag('h1');
>>> var h2 = makeTag('h2");
>>> ...
>>> ....
>>>
>>> for dozens of tags, and then use something like includeInThisContext....
>>> but I feel it's too weird.
>>>
>>> Apparently, my problem is: I didn't find a way to define a local var
>>> with a dynamic name.
>>>
>>> The original DSL in Ruby:
>>> https://github.com/dlitvakb/**deklarativna/blob/master/test/**
>>> test_deklarativna.rb<https://github.com/dlitvakb/deklarativna/blob/master/test/test_deklarativna.rb>
>>>
>>> use "include dslmodule". And inside the dsl module, it defines
>>> dynamically named functions at module top level. So the functions are
>>> automatically available to the module that makes the includes.
>>>
>>> That is the "trick" I didn't found how to emulate in
>>> Node.js/require/CommonJS world.
>>>
>>> Some links in my research:
>>> http://stackoverflow.com/**questions/5833978/javascript-**
>>> how-to-use-dynamic-local-**variables<http://stackoverflow.com/questions/5833978/javascript-how-to-use-dynamic-local-variables>
>>> http://stackoverflow.com/**questions/5094862/how-do-i-**
>>> access-a-local-variable-**dynamically-via-a-string-form-**
>>> of-its-name-fro<http://stackoverflow.com/questions/5094862/how-do-i-access-a-local-variable-dynamically-via-a-string-form-of-its-name-fro>
>>> http://stackoverflow.com/**questions/598878/how-can-i-**
>>> access-local-scope-**dynamically-in-javascript<http://stackoverflow.com/questions/598878/how-can-i-access-local-scope-dynamically-in-javascript>
>>> http://stackoverflow.com/**questions/2336508/javascript-**
>>> get-access-to-local-variable-**or-variable-in-closure-by-its-**name<http://stackoverflow.com/questions/2336508/javascript-get-access-to-local-variable-or-variable-in-closure-by-its-name>
>>> http://stackoverflow.com/**questions/1119335/javascript-**
>>> local-variable-declare<http://stackoverflow.com/questions/1119335/javascript-local-variable-declare>
>>>
>>> The better approach I found in these links is to use eval (!!??):
>>> eval("var "+name+ " = ....");
>>>
>>> Am I right? the only ways are the above ones? Or is another way?
>>>
>>> Any suggestions?
>>>
>>> Angel "Java" Lopez
>>>
>>>
>>> On Sat, Jul 7, 2012 at 9:27 AM, Mariusz Nowak <mari...@medikoo.com>wrote:
>>>
>>>> @ajlopez get to know how variable scoping in JavaScript works (what is
>>>> global, how this and how local variable works), and you'll get the answers
>>>> :)
>>>>
>>>>
>>>> On Saturday, July 7, 2012 2:11:56 PM UTC+2, ajlopez wrote:
>>>>>
>>>>> Hi people!
>>>>>
>>>>> A very simple question. When I write in the Node repl:
>>>>>
>>>>> this.foo = 'bar';
>>>>> console.log(foo);
>>>>>
>>>>> it's ok, foo is defined. But writing that code in file.js and running
>>>>>
>>>>> node file.js
>>>>>
>>>>> then foo is not defined.
>>>>>
>>>>> Or require('file.js'), then foo is not defined.
>>>>>
>>>>> Any way to define a variable in the "current context"? Apparently,
>>>>> "this" properties and "current context" top variables are the same in
>>>>> REPL,
>>>>> but they are not the same in .js, or inside a required module.
>>>>>
>>>>> I want to do this in a dynamic way:
>>>>>
>>>>> name = 'foo';
>>>>> // ...
>>>>> this[name] = 'bar';
>>>>>
>>>>> so
>>>>>
>>>>> foo = 'bar';
>>>>>
>>>>> is not a solution in my context.
>>>>>
>>>>> I could use:
>>>>>
>>>>> global[name] = 'bar';
>>>>>
>>>>> but I want to expose the new "current context" top variables only in
>>>>> my "current context" without pollute the global environment.
>>>>>
>>>>> I encountered this problem when coding a simple HTML DSL:
>>>>> https://github.com/ajlopez/**Sim**pleTags/blob/master/test/**expor**
>>>>> tsTo.js<https://github.com/ajlopez/SimpleTags/blob/master/test/exportsTo.js>
>>>>> I want the DSL functions to be accesible as:
>>>>>
>>>>> require('simpletags').**exportsT**o(????); // ???? == global? this?
>>>>> Now, I should use global to make it works in any situation
>>>>>
>>>>> then, use the exported function as functions in current context:
>>>>>
>>>>> html(body(h1("TheNextBigThing"****)));
>>>>>
>>>>> instead
>>>>>
>>>>> var st = require("simpletags");
>>>>>
>>>>> st.html(st.body(st.h1("**TheNext**BigThing")));
>>>>>
>>>>> Any other way?
>>>>>
>>>>> TIA
>>>>>
>>>>> Angel "Java" Lopez
>>>>> http://ajlopez.wordpress.com
>>>>> @ajlopez
>>>>> gh:ajlopez
>>>>>
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>>>
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