Interpolated CoffeeScript Filter for Blade

Why have one layer of variable insertion, when you could have twice the complexity?

The regular :coffeescript filter for Blade keeps #{} as the standard CoffeeScript interpolation, but doesn't let you use Blade variables in CoffeeScript snippets. blade-interpolated-coffee allows you to use ${} (or another symbol) to insert Blade variables into the block code.

- var url = "/";
:interpolatedcoffee
  i = 0
  console.log "i for '${url}' is #{i}"

Could produce the following HTML:

<script type="text/javascript">
  var i = 0;
  console.log("i for '/' is "+i);
</script>

Installation

npm install @codelenny/blade-interpolated-coffee

interpolatedCoffeeScript = require "@codelenny/blade-interpolated-coffee"
blade = require "blade"

blade.compile src,
    filters:
      interpolatedcoffee: interpolatedCoffeeScript
  , (err, html) -> # ...

Customization

Raw Filter

Don't want to have <script type="text/javascript"> automatically inserted? A raw mode is built in to the filter.

interpolatedCoffeeScript = require "@codelenny/blade-interpolated-coffee"

opts =
  filters:
    "$cs": interpolatedCoffeeScript
    "$cs.raw": interpolatedCoffeeScript.raw

script#main(data-i="0")
  :$cs.raw
    # ...

Change ${}

blade-interpolated-coffee ships with ${} as the default interpolation marker. However, you can use another marker:

interpolatedCoffeeScript = require "@codelenny/blade-interpolated-coffee"
myFilter = interpolatedCoffeeScript.custom /@\{/g
opts =
  filters:
    "$cs": myFilter
    "$cs.raw": myFilter.raw

custom takes two arguments: needle and haystack.

When blade-interpolated-coffee is given the contents of the text block, it passes the block to CoffeeScript (which interpolates uses of #{} with variables in the runtime scope).

Then all instances of needle are replaced with haystack, and the resulting string is passed to Blade. Blade will interpolate all inserted cases of #{} with variables in Blade's scope.

The marker could easily be changed by searching for /@\{/g as the needle, or more complex patterns can be created using both the needle and haystack, such as making sure that only single variables are interpolated.

complexFilter = interpolatedCoffeeScript.custom /\$\{([a-zA-Z_\s]+)\}/g, "\#{$1}"