Drop legacy node.js support, remove polyfills

package.json

@@ -24,12 +24,10 @@
     "postpublish": "git push origin +HEAD:latest --follow-tags"
   },
   "engines": {
-    "node": ">= 0.10.0"
+    "node": ">=12"
   },
   "dependencies": {
-    "raw-body": "2",
-    "through": "~2.3",
-    "when": "3"
+    "raw-body": "2"
   },
   "devDependencies": {
     "coffeescript": "^1.10.0",

src/io.coffee

@@ -1,23 +1,15 @@
-rawBody = require 'raw-body'
-When = require 'when'
-
-# It should work for any version of when.js
-nodefn = try
-  require 'when/node'
-catch
-  require 'when/node/function'
+streamToBuffer = require 'raw-body'
 
 {Buffer} = require 'buffer'
 {Stream, PassThrough} = require 'stream'
 
-streamToBuffer = nodefn.lift rawBody
-PassThrough ||= require 'through'
-
 bindCallback = (promise, next) ->
   if typeof next is 'function'
-    nodefn.bindCallback promise, next
-  else
-    promise
+    promise.then (result) ->
+      process.nextTick next, null, result
+    , (err) ->
+      process.nextTick next, err
+  promise
 
 module.exports =
   _write: (source, outname) ->
@@ -39,13 +31,13 @@ module.exports =
       source.pipe res.stdin
       res
     else
-      promise: When.reject new Error 'Mailformed source'
+      promise: Promise.reject new Error 'Mailformed source'
 
   write: (outname, next) ->
     promise = if outname
       (@_write @source, outname).promise
     else
-      When.reject new Error 'outname in not specified'
+      Promise.reject new Error 'outname in not specified'
     bindCallback promise, next
 
   toBuffer: (next) ->
@@ -59,9 +51,9 @@ module.exports =
       res.promise
     else
       res.promise.then ->
-        When.reject new Error 'Failed to pipe stdout'
+        Promise.reject new Error 'Failed to pipe stdout'
     promise.then ->
       outstream.end()
-    .otherwise (err) ->
+    .catch (err) ->
       outstream.emit 'error', err
     outstream

src/wrapper.coffee

@@ -1,8 +1,13 @@
-When = require 'when'
 {spawn} = require 'child_process'
 
 {mixin} = require './utils'
 
+defer = () ->
+  res = {}
+  res.promise = new Promise (resolve, reject) ->
+    res.resolve = resolve
+    res.reject = reject
+  res
 
 module.exports = class Wrapper
   mixin this, require './args'
@@ -20,7 +25,7 @@ module.exports = class Wrapper
     return @
 
   _spawn: (args, stdin = false, stdout = false) ->
-    {resolve, reject, promise} = When.defer()
+    {resolve, reject, promise} = defer()
     stderr = ''
     @_opts.stdio = [
       if stdin  then 'pipe' else 'ignore'
@@ -40,7 +45,7 @@ module.exports = class Wrapper
         resolve()
     proc.stderr.on 'data', onErrData = (data) ->
       stderr += data
-    promise = promise.ensure ->
+    promise = promise.finally ->
       # Cleanup
       proc.removeListener 'error', onError
       proc.removeListener 'close', onClose

test/io.coffee

@@ -1,12 +1,9 @@
-rawBody = require 'raw-body'
-nodefn = require 'when/node'
+streamToBuffer = require 'raw-body'
 {ReadableStreamBuffer} = require 'stream-buffers'
 
 {Buffer} = require 'buffer'
 {Stream} = require 'stream'
 
-streamToBuffer = nodefn.lift rawBody
-
 run_mocked 'io', (Webp, {read, write}) ->
 
   describe 'output', ->

test/main.coffee

@@ -25,5 +25,5 @@ run_tests 'main', (Webp) ->
       {stdout, stderr} = proc
       stdout.listeners('data').should.be.empty
       stderr.listeners('data').should.be.empty
-    .ensure ->
+    .finally ->
       child_process.spawn = spawn