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 lib
    mkdir lib

watch:
    @./node_modules/coffee-script/bin/coffee \
        -o lib \
        -cw src

test:
    @./node_modules/mocha/bin/mocha \
        --reporter $(REPORTER) \
        test/*.coffee

.PHONY: build clean watch test

The project root directory has a test folder with two files: mocha.opts and example.coffee

example.coffee - Content

describe "feature", ->
   it "should add two numbers", ->
       (2+2).should.equal 4

On running make test, getting the following error:

cribe 'feature',
      ^^^^^^^^^

node.js:201
        throw e; // process.nextTick error, or 'error' event on first tick
              ^
SyntaxError: Unexpected string
    at Module._compile (module.js:429:25)
    at Object..js (module.js:459:10)
    at Module.load (module.js:348:31)
    at Function._load (module.js:308:12)
    at Module.require (module.js:354:17)
    at require (module.js:370:17)
    at /home/my_username/testcode/coffeepress/node_modules/mocha/bin/_mocha:261:27
    at Array.forEach (native)
    at load (/home/my_username/testcode/coffeepress/node_modules/mocha/bin/_mocha:258:9)
    at Object.<anonymous> (/home/my_username/testcode/coffeepress/node_modules/mocha/bin/_mocha:249:1)
    at Module._compile (module.js:441:26)
    at Object..js (module.js:459:10)
    at Module.load (module.js:348:31)
    at Function._load (module.js:308:12)
    at Array.0 (module.js:479:10)
    at EventEmitter._tickCallback (node.js:192:40)

Running Mocha with js files succeeds, but cannot get it to run with CoffeeScript. I really want to - for code brevity.

Please guide.

score 88 · Accepted Answer · edited Feb 11 '14 at 05:44

88

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.

edited Feb 11 '14 at 05:44

epidemian

18,817
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answered Mar 30 '12 at 12:46

Trevor Burnham

76,828
33
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196

That link is broken and `--compilers` has been deprecated https://github.com/mochajs/mocha/wiki/compilers-deprecation – Maria Ines Parnisari Feb 27 '22 at 00:10

score 28 · Answer 2 · answered Jan 30 '14 at 00:10

28

From CoffeeScript 1.7 onwards, the option should be:

--compilers coffee:coffee-script/register

An issue was filed on Mocha's github site.

answered Jan 30 '14 at 00:10

Louis

146,715
28
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Maybe update this to reflect v2 onwards and thus the lack of a dash. `coffee:coffeescript/register` worked for me – aaaaaa Jan 23 '18 at 19:52

palsch · Answer 3 · 2018-06-09T23:59:20.980

2

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.

edited Jun 09 '18 at 23:59

answered Jun 09 '18 at 23:43

palsch

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Depending on whether you have the older `coffee-script` or the new `coffeescript` (no dash) installed from npm, you will need `--require coffee-script/register` or `--require coffeescript/register`. – palsch Jun 10 '18 at 00:00

score 1 · Answer 4 · answered Jun 09 '18 at 00:46

1

mocha --require coffeescript/register

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

answered Jun 09 '18 at 00:46

André Willik Valenti

1,702
14
21

score 1 · Answer 5 · answered Apr 27 '20 at 06:16

1

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

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

answered Apr 27 '20 at 06:16

5warag

46
2

score 0 · Answer 6 · answered Apr 23 '14 at 15:22

0

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

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

answered Apr 23 '14 at 15:22

Evan Moran

3,825
34
20

Cannot run Mocha with CoffeeScript

6 Answers6

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