Don’t patch Error.prepareStackTrace if --enable-source-maps is used.

docs/v2/test.html

@@ -32712,6 +32712,7 @@ <h2>Another heading</h2>
 <script type="text/x-coffeescript" class="test" id="sourcemap">
 return if global.testingBrowser
 
+{spawn, fork} = require('child_process')
 SourceMap = require '../src/sourcemap'
 
 vlqEncodedValues = [
@@ -32776,6 +32777,125 @@ <h2>Another heading</h2>
   arrayEq v3SourceMap.sources, ['tempus_fugit.coffee']
   eq v3SourceMap.sourceRoot, './www_root/coffee/'
 
+test "node --enable-source-map built in stack trace mapping", ->
+  new Promise (resolve, reject) ->
+    proc = fork './test/importing/error.coffee', [
+      '--enable-source-maps'
+    ], stdio: 'pipe'
+
+    err = ''
+    proc.stderr.setEncoding 'utf8'
+    proc.stderr.on 'data', (str) -> err += str
+    proc.on 'close', ->
+      try
+        match = err.match /error\.coffee:(\d+):(\d+)/
+        throw new Error err unless match
+
+        [_, line, column] = match
+        equal line, 3 # Mapped source line
+        equal column, 9 # Mapped source column
+
+        resolve()
+      catch exception
+        reject exception
+
+if Number(process.versions.node.split('.')[0]) >= 14
+  test "NODE_OPTIONS=--enable-source-maps environment variable stack trace mapping", ->
+    new Promise (resolve, reject) ->
+      proc = fork './test/importing/error.coffee', [],
+        env:
+          NODE_OPTIONS: '--enable-source-maps'
+        stdio: 'pipe'
+
+      err = ''
+      proc.stderr.setEncoding 'utf8'
+      proc.stderr.on 'data', (str) -> err += str
+      proc.on 'close', ->
+        try
+          match = err.match /error\.coffee:(\d+):(\d+)/
+          throw new Error err unless match
+
+          [_, line, column] = match
+          equal line, 3 # Mapped source line
+          equal column, 9 # Mapped source column
+
+          resolve()
+        catch exception
+          reject exception
+
+  test "generate correct stack traces with --enable-source-maps from bin/coffee", ->
+    new Promise (resolve, reject) ->
+      proc = fork 'test/importing/error.coffee',
+        ['--enable-source-maps'],
+        stdio: 'pipe'
+
+      err = ""
+      proc.stderr.setEncoding 'utf8'
+      proc.stderr.on 'data', (str) -> err += str
+      proc.on 'close', ->
+        try
+          match = err.match /error\.coffee:(\d+):(\d+)/
+          throw new Error err unless match
+
+          [_, line, column] = match
+          equal line, 3 # Mapped source line
+          equal column, 9 # Mapped source column
+
+          resolve()
+        catch exception
+          reject exception
+
+test "don't change stack traces if another library has patched `Error.prepareStackTrace`", ->
+  new Promise (resolve, reject) ->
+    # This uses `spawn` rather than the preferred `fork` because `fork` requires
+    # loading code in a separate file. The `--eval` here shows exactly what is
+    # executing without indirection.
+    proc = spawn 'node', [
+      '--eval', """
+        const patchedPrepareStackTrace = Error.prepareStackTrace = function() {};
+        require('./register.js');
+        process.stdout.write(Error.prepareStackTrace === patchedPrepareStackTrace ? 'preserved' : 'overwritten');
+      """
+    ]
+
+    out = ''
+    proc.stdout.setEncoding 'utf8'
+    proc.stdout.on 'data', (str) -> out += str
+
+    proc.on 'close', (status) ->
+      try
+        equal status, 0
+        equal out, 'preserved'
+
+        resolve()
+      catch exception
+        reject exception
+
+test "requiring 'CoffeeScript' doesn't change `Error.prepareStackTrace`", ->
+  new Promise (resolve, reject) ->
+    # This uses `spawn` rather than the preferred `fork` because `fork` requires
+    # loading code in a separate file. The `--eval` here shows exactly what is
+    # executing without indirection.
+    proc = spawn 'node', [
+      '--eval', """
+        require('./lib/coffeescript/coffeescript.js');
+        process.stdout.write(Error.prepareStackTrace === undefined ? 'unused' : 'defined');
+      """
+    ]
+
+    out = ''
+    proc.stdout.setEncoding 'utf8'
+    proc.stdout.on 'data', (str) -> out += str
+
+    proc.on 'close', (status) ->
+      try
+        equal status, 0
+        equal out, 'unused'
+
+        resolve()
+      catch exception
+        reject exception
+
 </script>
 <script type="text/x-coffeescript" class="test" id="strict">
 # Strict Early Errors

documentation/site/docs.coffee

@@ -14,6 +14,8 @@ window.gtag 'config', window.GA_TRACKING_ID
 
 # Initialize the CoffeeScript docs interactions
 $(document).ready ->
+  CoffeeScript.patchStackTrace()
+
   # Format dates for the user’s locale, e.g. 'December 24, 2009' or '24 décembre 2009'
   $('time').each (index, el) ->
     date = el.dateTime or $(el).text()
@@ -105,11 +107,17 @@ $(document).ready ->
                 if window.localStorage?
                   window.localStorage.setItem 'tryCoffeeScriptCode', coffee
               catch exception
-            output = CoffeeScript.compile coffee, bare: yes
+
+            js = CoffeeScript.compile coffee, bare: yes, inlineMap: true
+            # Inline map is added to adjust stack trace line numbers but we strip it from the displayed JS for visual clarity.
+            output = js.replace /(\n\/\/# [^\n]*){2}$/, ""
             lastCompilationElapsedTime = Math.max(200, Date.now() - lastCompilationStartTime)
           catch exception
             output = "#{exception}"
+
+          editors[index + 1].js = js
           editors[index + 1].setValue output
+
           gtag 'event', 'edit_code',
             event_category: 'engagement'
             event_label: $textarea.closest('[data-example]').data('example')
@@ -149,7 +157,7 @@ $(document).ready ->
     run = $(@).data 'run'
     index = $("##{$(@).data('example')}-js").data 'index'
     js = if editors[index]?
-      editors[index].getValue()
+      editors[index].js
     else
       $(textareas[index]).val()
     js = "#{js}\nalert(#{unescape run});" unless run is yes