Add ESM support, decouple from underscore.js

.gitignore

@@ -2,3 +2,4 @@ node_modules
 *~
 .*.swp
 *.js
+/.history/

.nvmrc

@@ -1 +1 @@
-12
+18

Makefile

@@ -1,20 +1,33 @@
 .PHONY: build test tag
 
 TESTS=$(shell cd test && ls *.coffee | sed s/\.coffee$$//)
+ESMTESTS=$(shell cd test/ESM && ls *.coffee | sed s/\.coffee$$//)
 
 build: underscore.deep.js
 
-underscore.deep.js: underscore.deep.coffee
-	node_modules/coffee-script/bin/coffee --bare -c underscore.deep.coffee
+# compile coffeescript files to ./dist/esm
+coffeescript-compile-to-esm:
+	node_modules/.bin/coffee --bare -o dist/esm -c src/*.coffee
 
-test: $(TESTS) README.coffee.md
+# transpile ESM to CJS using mkdist
+mkdist: coffeescript-compile-to-esm
+	node_modules/.bin/mkdist . --src=dist/esm --dist=dist/cjs --format=cjs --pattern='*.js'
+
+underscore.deep.js: mkdist
+
+test: $(TESTS) README.coffee.md $(ESMTESTS)
 
 README.coffee.md: build
-	node_modules/mocha/bin/mocha --reporter spec --compilers coffee:coffee-script README.coffee.md
+	node_modules/.bin/mocha --reporter spec --require coffeescript/register README.coffee.md
 
 $(TESTS): build
 	@echo $(LIBS)
-	node_modules/mocha/bin/mocha --bail --timeout 60000 --compilers coffee:coffee-script test/$@.coffee
+	node_modules/.bin/mocha --bail --timeout 60000 --require coffeescript/register test/$@.coffee
+
+$(ESMTESTS): build
+	@echo $(ESMLIBS)
+	node_modules/.bin/coffee --bare -c test/ESM/$@.coffee
+	node_modules/.bin/mocha --bail --timeout 60000 --input-type=module test/ESM/$@.js
 
 tag:
 	$(eval VERSION := $(shell grep version package.json | sed -ne 's/^[ ]*"version":[ ]*"\([0-9\.]*\)",/\1/p';))

README.coffee.md

@@ -22,6 +22,24 @@ npm install underscore.deep
 
 ## Usage
 
+Javascript (EcmaScript module):
+
+```js
+import _ from 'underscore';
+import underscoreDeep from 'underscore.deep';
+_.mixin(underscoreDeep);
+```
+
+Javascript (CommonJS module):
+
+```js
+const _ = require('underscore');
+const underscoreDeep = require('underscore.deep');
+_.mixin(underscoreDeep);
+```
+
+CoffeeScript:
+
 ```
 _ = require 'underscore'
 _.mixin require 'underscore.deep'
@@ -32,7 +50,7 @@ _.mixin require 'underscore.deep'
     describe 'underscore.deep', ->
       assert = require 'assert'
       _ = require 'underscore'
-      _.mixin require './underscore.deep'
+      _.mixin require 'underscore.deep'
 
 ### _.deepToFlat(obj)