can rewire worked with module exported functions? about rewire

[jhnns]

rewire adds the setters and getters to the exports-object at the bottom of the module. Just imagine that rewire injects code at the bottom of your module that looks like:

exports.__set__ = function () { ... };
exports.__get__ = function () { ... };

So if you do module.exports = helper, the setters and getters will be attached to the helper-function itself, not to the object returned by calling helper(app).

[gprasant]

Does that mean the only way to be able to use rewire on a module is to
export an object and not export a function ? Do you know of any way to use
rewire with the module pattern ?
On Nov 7, 2013 6:47 PM, "Johannes Ewald" [email protected] wrote:

rewire adds the setters and getters to the exports-object at the bottom
of the module. Just imagine that rewire injects code at the bottom of your
module that looks like:

exports.set = function () { ... }:exports.get = function () { ... };

So if you do module.exports = helper, the setters and getters will be
attached to the helper-object, not to the object returned by calling
helper(app).

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/22#issuecomment-27961747
.

[jhnns]

rewire still works when exporting a function. If you place your variables you want to mock in the top-level scope of the module, it should be no problem. Given this module:

var http = require("http"),
      fs = require("fs");

function helper(app) {
    return {
        get_watch_list: function () { ... }
        update_watch_list: function (r_ip) { ... }
    };
}

module.exports = helper;

you can still inject mocks for the http- and the fs-module. Just write

var helper = rewire ("./helper");

helper.__set__("http", { ... });
helper.__set__("fs", { ... });

[davidposin]

@gprasant You can but you can only interact with variables at the "top" level. You can't override http.get but you can override the http object to have a custom get function.

I put together a sample on c9 where I override http.get here that might help:
https://c9.io/dposin/jasmine-node-rewire

Also, I have a post that walks through rewire and jasmine-node:
http://randomjavascript.blogspot.com/2013/10/jasmine-node-and-rewire-part-1.html

Hope this helps.

[gprasant]

Thanks @Lastalas .

@jhnns

var helper = rewire ("./helper");

helper.__set__("http", { ... });
helper.__set__("fs", { ... });

# use test_helper for calling functions & user helper for __set__ and __get__ . 
test_helper = helper(app_stub);

This is the style Im going ahead with. Looks good? Better Ideas?

[jhnns]

Looks good! 👍

Thanks @Lastalas for your detailed blog post. Wish I had more time to write such posts...
Just found two things:

• the link to rewire isn't working
• you don't need the __dirname-thing in rewire(__dirname + '/server.js'). rewire works just like require and will resolve any relative paths to the current module

[davidposin]

@jhnns I fixed the link. thanks for spotting that.

The __dirname was because of the way c9 handles the actual file structure. I'll look and see if I can remove it.