From 7de06c3dcba319cace960ddd5bcaa2ebf0e95bfd Mon Sep 17 00:00:00 2001
From: Geoffrey Booth <webmaster@geoffreybooth.com>
Date: Mon, 20 Feb 2017 15:32:11 -0800
Subject: [PATCH] =?UTF-8?q?Ensure=20unique=20source=20maps=E2=80=99=20sour?=
 =?UTF-8?q?ceURL;=20closes=20#4126?=
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---
 lib/coffeescript/browser.js | 2 ++
 src/browser.coffee          | 7 +++++++
 2 files changed, 9 insertions(+)

diff --git a/lib/coffeescript/browser.js b/lib/coffeescript/browser.js
index a2dd3de2..4afb4c81 100644
--- a/lib/coffeescript/browser.js
+++ b/lib/coffeescript/browser.js
@@ -92,11 +92,13 @@
       };
       source = script.src || script.getAttribute('data-src');
       if (source) {
+        options.filename = source;
         return CoffeeScript.load(source, function(param) {
           coffees[i] = param;
           return execute();
         }, options, true);
       } else {
+        options.filename = script.id && script.id !== '' ? script.id : `coffeescript${(i !== 0 ? i : '')}`;
         options.sourceFiles = ['embedded'];
         return coffees[i] = [script.innerHTML, options];
       }
diff --git a/src/browser.coffee b/src/browser.coffee
index f1903237..8fdaab14 100644
--- a/src/browser.coffee
+++ b/src/browser.coffee
@@ -69,6 +69,7 @@ runScripts = ->
       options = literate: script.type is coffeetypes[1]
       source = script.src or script.getAttribute('data-src')
       if source
+        options.filename = source
         CoffeeScript.load source,
           (param) ->
             coffees[i] = param
@@ -76,6 +77,12 @@ runScripts = ->
           options
           true
       else
+        # `options.filename` defines how the filename the source map appears as
+        # in Developer Tools. If a script tag has an `id`, use that as the
+        # filename; otherwise use `coffeescript`, or `coffeescript1` etc.
+        # leaving the first one unnumbered for the common case that there’s
+        # only one CoffeeScript script block to parse.
+        options.filename = if script.id and script.id isnt '' then script.id else "coffeescript#{if i isnt 0 then i else ''}"
         options.sourceFiles = ['embedded']
         coffees[i] = [script.innerHTML, options]