Add optional output argument to mustache bin

[wizawu]

I am not sure whether this PR is welcome, since I didn't see much people had a requirement for using this argument.
Yet we have been using this feature in production (because > output is forbidden in certain cases).
Feel free to close it if you find it confusing.
Thanks.

[phillipj]

Seems like a good feature 👍 Could you please add atleast one test for it aswell?

[wizawu]

Sorry, test added now.
I think probably I shouldn't update the README. It might cause a mess 😞

[phillipj]

I'm thinking this file shouldn't be commited, it would even be better if it were deleted after the tests has run.

When this file exists in the repo, your changes in ./bin/mustache could actually be reverted, and the test below would still pass - right?

[phillipj]

Sorry, test added now.

Nice! One little comment about the output file, otherwise it LGTM.

[wizawu]

Done 💪

[phillipj]

Thanks! 👍

[dasilvacontin]

Btw @wizawu, what's the case in which > output is forbidden? I'm curious. :)

[wizawu]

When using ansible's shell module.

- name: append
  shell: mustache .... >> output

- name: there won't be output
  shell: mustache .... > output

Apparently we don't want to append to output.

[dasilvacontin]

@wizawu But does it raise an error, or?

Have you checked ansible/ansible#9791 and/or http://docs.ansible.com/ansible/shell_module.html, specially:

# Run a command that uses non-posix shell-isms (in this example /bin/sh
# doesn't handle redirection and wildcards together but bash does)
- shell: cat < /tmp/*txt
  args:
    executable: /bin/bash

[wizawu]

It won't raise an error. It would exit normally, but without any output. I know it is not a bug of mustache.

And yes, I've checked those docs. Thanks :) I just thought adding a third argument would be easier for me. I do agree that it is just an uncommon scene.

There is another case in package.json

{
  "scripts": {
    "build:html": "mustache view.json",
    "build:html:all": "ls html | xargs -I {} npm run build:html {} > dist/{}",
  }
}

The second script won't work as expected, since > dist/{} won't be concated to build:html.

I also agree that it is another uncommon scene.

[phillipj]

FYI if you'd like to send custom arguments to a npm script, like it seems you're trying to with build:html, you'll have to use double dash before any of the arguments arguments. E.g. npm run build:html -- page.html

Read more about it in npm run script docs.

[wizawu]

@phillipj Very useful!

But after all, > won't be treated as an argument.