Cannot run Mocha with CoffeeScript

Question

Makefile - Content:

REPORTER = dot

all: build

build:
    @./node_modules/coffee-script/bin/coffee \\
        -c \\
        -o lib src

clean:
    rm -rf li         


        

Answer 1

Apparently, a change in Mocha made in April 2018 (softly) deprecated the --compilers option. In the command line you now get:

(node:27864) DeprecationWarning: "--compilers" will be removed in a future version of Mocha; see https://git.io/vdcSr for more info

Like the link says, this can easily be fixed by just not using --compilers and using this new (simplified) mocha.opts options:

--require coffeescript/register

test/*.coffee

The last line is needed to make Mocha understand it should now use *.coffee files as test files. This seems not to be covered with the --require option.

Answer 2

I needed two changes to my mocha args to get this to work:

--require coffee-script/register
--compilers coffee:coffee-script/register

Answer 3

As of Mocha 1.0:

coffee-script is no longer supported out of the box. CS and similar transpilers may be used by mapping the file extensions (for use with --watch) and the module name. For example --compilers coffee:coffee-script with CoffeeScript 1.6- or --compilers coffee:coffee-script/register with CoffeeScript 1.7+.

(Quoting http://visionmedia.github.io/mocha/#compilers-option) So, you need to add the line

--compilers coffee:coffee-script/register

or, for CS <= 1.6.x,

--compilers coffee:coffee-script

to your mocha.opts file.

Answer 4

From CoffeeScript 1.7 onwards, the option should be:

--compilers coffee:coffee-script/register

An issue was filed on Mocha's github site.

Answer 5

with the latest update of mocha the the require statement must written in package.json file as

  "mocha":{
    "require":"coffeescript",
    "reporter":"spec"
  },

Answer 6

mocha --require coffeescript/register

Source: https://github.com/mochajs/mocha/wiki/compilers-deprecation