From bf061bede4b0280654c25b19fc3cc34e25d13cf0 Mon Sep 17 00:00:00 2001
From: Naina Raisinghani <nainar@google.com>
Date: Mon, 27 Apr 2020 11:29:31 -0700
Subject: [PATCH 01/26] Create CODE_OF_CONDUCT.md (#410)

---
 CODE_OF_CONDUCT.md | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 CODE_OF_CONDUCT.md

diff --git a/CODE_OF_CONDUCT.md b/CODE_OF_CONDUCT.md
new file mode 100644
index 000000000..b74de28e0
--- /dev/null
+++ b/CODE_OF_CONDUCT.md
@@ -0,0 +1 @@
+See https://github.com/ampproject/meta/blob/master/CODE_OF_CONDUCT.md

From 47b50005d6cb5de1fd8023c36b44a681ed37ddc0 Mon Sep 17 00:00:00 2001
From: Derek Tse <xiexr151e@gmail.com>
Date: Fri, 10 Jul 2020 00:59:24 -0700
Subject: [PATCH 02/26] initial creation of transformer

---
 transformer/transformers/scriptsrcrewrite.go  | 62 +++++++++++++++++++
 .../transformers/scriptsrcrewrite_test.go     |  0
 2 files changed, 62 insertions(+)
 create mode 100644 transformer/transformers/scriptsrcrewrite.go
 create mode 100644 transformer/transformers/scriptsrcrewrite_test.go

diff --git a/transformer/transformers/scriptsrcrewrite.go b/transformer/transformers/scriptsrcrewrite.go
new file mode 100644
index 000000000..8fe6e76ed
--- /dev/null
+++ b/transformer/transformers/scriptsrcrewrite.go
@@ -0,0 +1,62 @@
+package transformers
+
+import (
+	"regexp"
+	"strings"
+
+	"github.com/ampproject/amppackager/transformer/internal/amphtml"
+	"github.com/ampproject/amppackager/transformer/internal/htmlnode"
+	"golang.org/x/net/html/atom"
+	"golang.org/x/net/html"
+)
+
+type rewritable interface {
+	// Rewrite the URLs within
+	rewrite(string, *url.URL, string, nodeMap)
+}
+
+type urlRewriteContext []rewritable
+
+// textNodeContext qualifies a text node, whose entire data value has URLs embedded
+// within. This struct keeps track of where the URLs occur in the body of the text.
+type textNodeContext struct {
+	node    *html.Node
+	offsets []amphtml.SubresourceOffset
+}
+
+// This matches strings that end with ".js".
+var jsRE = func() *regexp.Regexp {
+	r = regexp.MustCompile("^(.)*\.js")
+	return r
+}()
+
+// This matches strings that end with ".sxg.js".
+var sxgJsRE = func() *regexp.Regexp {
+	r = regexp.MustCompile("^(.)*\.sxg\.js")
+	return r
+}()
+
+// ScriptSrcRewrite rewrites the value of src in <script> elements, where applicable.
+// If the value is of the form "*.js" (and not already "*.sxg.js"), replace it with "*.sxg.js".
+func ScriptSrcRewrite(e *Context) error {
+	for n := e.DOM.RootNode; n != nil; n = htmlnode.Next(n) {
+		if n.Type != html.ElementNode {
+			continue
+		}
+
+		if n.DataAtom == atom.Script {
+			srcVal, srcOk := htmlnode.GetAttributeVal(n, "", "src")
+			if srcOk {
+				matchJsRE := jsRE.MatchString(srcVal)
+				matchSxgJsRE := sxgJsRE.MatchString(srcVal)
+				if matchJsRE && !matchSxgJsRE {
+					// Rewrite logic here
+					continue
+				}
+			}
+		} else {
+			continue
+		}
+	}
+	return nil
+}
\ No newline at end of file
diff --git a/transformer/transformers/scriptsrcrewrite_test.go b/transformer/transformers/scriptsrcrewrite_test.go
new file mode 100644
index 000000000..e69de29bb

From 9e0261743ee19c3495c45452cf833547e79e4230 Mon Sep 17 00:00:00 2001
From: Derek Tse <xiexr151e@gmail.com>
Date: Fri, 10 Jul 2020 18:31:41 -0700
Subject: [PATCH 03/26] updated transformer after consultation

---
 transformer/transformer.go                    |  2 +
 transformer/transformers/scriptsrcrewrite.go  | 43 ++----------
 .../transformers/scriptsrcrewrite_test.go     | 70 +++++++++++++++++++
 3 files changed, 77 insertions(+), 38 deletions(-)

diff --git a/transformer/transformer.go b/transformer/transformer.go
index 258f45912..969757123 100644
--- a/transformer/transformer.go
+++ b/transformer/transformer.go
@@ -44,6 +44,7 @@ var transformerFunctionMap = map[string]func(*transformers.Context) error{
 	"absoluteurl":           transformers.AbsoluteURL,
 	"ampboilerplate":        transformers.AMPBoilerplate,
 	"ampruntimecss":         transformers.AMPRuntimeCSS,
+	"ampruntimejs":			 transformers.AMPRuntimeJS,
 	"linktag":               transformers.LinkTag,
 	"nodecleanup":           transformers.NodeCleanup,
 	"preloadimage":          transformers.PreloadImage,
@@ -72,6 +73,7 @@ var configMap = map[rpb.Request_TransformersConfig][]func(*transformers.Context)
 		transformers.AMPRuntimeCSS,
 		transformers.TransformedIdentifier,
 		transformers.URLRewrite,
+		transformers.AMPRuntimeJS,
 		transformers.PreloadImage,
 		// ReorderHead should run after all transformers that modify the
 		// <head>, as they may do so without preserving the proper order.
diff --git a/transformer/transformers/scriptsrcrewrite.go b/transformer/transformers/scriptsrcrewrite.go
index 8fe6e76ed..400ed50ad 100644
--- a/transformer/transformers/scriptsrcrewrite.go
+++ b/transformer/transformers/scriptsrcrewrite.go
@@ -10,49 +10,16 @@ import (
 	"golang.org/x/net/html"
 )
 
-type rewritable interface {
-	// Rewrite the URLs within
-	rewrite(string, *url.URL, string, nodeMap)
-}
-
-type urlRewriteContext []rewritable
-
-// textNodeContext qualifies a text node, whose entire data value has URLs embedded
-// within. This struct keeps track of where the URLs occur in the body of the text.
-type textNodeContext struct {
-	node    *html.Node
-	offsets []amphtml.SubresourceOffset
-}
-
-// This matches strings that end with ".js".
-var jsRE = func() *regexp.Regexp {
-	r = regexp.MustCompile("^(.)*\.js")
-	return r
-}()
-
-// This matches strings that end with ".sxg.js".
-var sxgJsRE = func() *regexp.Regexp {
-	r = regexp.MustCompile("^(.)*\.sxg\.js")
-	return r
-}()
-
-// ScriptSrcRewrite rewrites the value of src in <script> elements, where applicable.
-// If the value is of the form "*.js" (and not already "*.sxg.js"), replace it with "*.sxg.js".
-func ScriptSrcRewrite(e *Context) error {
+// AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
+// If the value is of the form "*.js", replace it with "*.sxg.js".
+func AMPRuntimeJS(e *Context) error {
 	for n := e.DOM.RootNode; n != nil; n = htmlnode.Next(n) {
 		if n.Type != html.ElementNode {
 			continue
 		}
-
 		if n.DataAtom == atom.Script {
-			srcVal, srcOk := htmlnode.GetAttributeVal(n, "", "src")
-			if srcOk {
-				matchJsRE := jsRE.MatchString(srcVal)
-				matchSxgJsRE := sxgJsRE.MatchString(srcVal)
-				if matchJsRE && !matchSxgJsRE {
-					// Rewrite logic here
-					continue
-				}
+			if src, ok = htmlnode.FindAttribute(n, "", "src"); ok && strings.hasPrefix(src.Val, amphtml.AMPCacheRootURL) && strings.HasSuffix(src.Val, ".js"){
+				src.Val = strings.TrimSuffix(src.Val, ".js") + ".sxg.js"
 			}
 		} else {
 			continue
diff --git a/transformer/transformers/scriptsrcrewrite_test.go b/transformer/transformers/scriptsrcrewrite_test.go
index e69de29bb..7c598f7db 100644
--- a/transformer/transformers/scriptsrcrewrite_test.go
+++ b/transformer/transformers/scriptsrcrewrite_test.go
@@ -0,0 +1,70 @@
+package transformers_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/ampproject/amppackager/transformer/internal/amphtml"
+	tt "github.com/ampproject/amppackager/transformer/internal/testing"
+	"github.com/ampproject/amppackager/transformer/transformers"
+	"golang.org/x/net/html"
+)
+
+func TestStripJS(t *testing.T) {
+	tcs := []tt.TestCase{
+		{
+			Desc:     "no script node",
+			Input:    "<head></head><body></body>",
+			Expected: "<head></head><body></body>",
+		},
+		{
+			Desc:     "no prefix",
+			Input:    "<script src=main.js/>",
+			Expected: "<script src=main.js/>",
+		},
+		{
+			Desc:     "no suffix",
+			Input:    "<script src=\"https://cdn.ampproject.org\"/>",
+			Expected: "<script src=\"https://cdn.ampproject.org\"/>",
+		},
+		{
+			Desc:     "transformation",
+			Input:    "<script async src=\"https://cdn.ampproject.org/v0.js\"></script>",
+			Expected: "<script async src=\"https://cdn.ampproject.org/v0.sxg.js\"></script>",
+		},
+	}
+
+	for _, tc := range tcs {
+		inputDoc, err := html.Parse(strings.NewReader(tc.Input))
+		if err != nil {
+			t.Errorf("%s: html.Parse failed %q", tc.Input, err)
+			continue
+		}
+		inputDOM, err := amphtml.NewDOM(inputDoc)
+		if err != nil {
+			t.Errorf("%s\namphtml.NewDOM for %s failed %q", tc.Desc, tc.Input, err)
+			continue
+		}
+		transformers.AMPRuntimeJS(&transformers.Context{DOM: inputDOM})
+		var input strings.Builder
+		if err := html.Render(&input, inputDoc); err != nil {
+			t.Errorf("%s: html.Render failed %q", tc.Input, err)
+			continue
+		}
+
+		expectedDoc, err := html.Parse(strings.NewReader(tc.Expected))
+		if err != nil {
+			t.Errorf("%s: html.Parse failed %q", tc.Expected, err)
+			continue
+		}
+		var expected strings.Builder
+		err = html.Render(&expected, expectedDoc)
+		if err != nil {
+			t.Errorf("%s: html.Render failed %q", tc.Expected, err)
+			continue
+		}
+		if input.String() != expected.String() {
+			t.Errorf("%s: Transform=\n%q\nwant=\n%q", tc.Desc, &input, &expected)
+		}
+	}
+}
\ No newline at end of file

From dff39de9a7683c78bb4a98f76574ce1dd653ffbc Mon Sep 17 00:00:00 2001
From: Derek Tse <xiexr151e@gmail.com>
Date: Fri, 10 Jul 2020 18:38:38 -0700
Subject: [PATCH 04/26] transformer rename

---
 transformer/transformers/{scriptsrcrewrite.go => ampruntimejs.go} | 0
 .../{scriptsrcrewrite_test.go => ampruntimejs_test.go}            | 0
 2 files changed, 0 insertions(+), 0 deletions(-)
 rename transformer/transformers/{scriptsrcrewrite.go => ampruntimejs.go} (100%)
 rename transformer/transformers/{scriptsrcrewrite_test.go => ampruntimejs_test.go} (100%)

diff --git a/transformer/transformers/scriptsrcrewrite.go b/transformer/transformers/ampruntimejs.go
similarity index 100%
rename from transformer/transformers/scriptsrcrewrite.go
rename to transformer/transformers/ampruntimejs.go
diff --git a/transformer/transformers/scriptsrcrewrite_test.go b/transformer/transformers/ampruntimejs_test.go
similarity index 100%
rename from transformer/transformers/scriptsrcrewrite_test.go
rename to transformer/transformers/ampruntimejs_test.go

From b099fd13217ca2c2c85713094e6349acf2988fa7 Mon Sep 17 00:00:00 2001
From: Derek Tse <xiexr151e@gmail.com>
Date: Mon, 10 Aug 2020 22:21:00 -0700
Subject: [PATCH 05/26] .sxg.js to &f=sxg

---
 transformer/transformers/ampruntimejs.go      | 2 +-
 transformer/transformers/ampruntimejs_test.go | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index 400ed50ad..41656413c 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -19,7 +19,7 @@ func AMPRuntimeJS(e *Context) error {
 		}
 		if n.DataAtom == atom.Script {
 			if src, ok = htmlnode.FindAttribute(n, "", "src"); ok && strings.hasPrefix(src.Val, amphtml.AMPCacheRootURL) && strings.HasSuffix(src.Val, ".js"){
-				src.Val = strings.TrimSuffix(src.Val, ".js") + ".sxg.js"
+				src.Val = strings.TrimSuffix(src.Val, ".js") + ".js&f=sxg"
 			}
 		} else {
 			continue
diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index 7c598f7db..eaa3a53c0 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -30,7 +30,7 @@ func TestStripJS(t *testing.T) {
 		{
 			Desc:     "transformation",
 			Input:    "<script async src=\"https://cdn.ampproject.org/v0.js\"></script>",
-			Expected: "<script async src=\"https://cdn.ampproject.org/v0.sxg.js\"></script>",
+			Expected: "<script async src=\"https://cdn.ampproject.org/v0.js&f=sxg\"></script>",
 		},
 	}
 

From 81b97fbb8205fd9c3bdb812009c1454b2c8d838d Mon Sep 17 00:00:00 2001
From: Derek Tse <xiexr151e@gmail.com>
Date: Mon, 10 Aug 2020 22:46:23 -0700
Subject: [PATCH 06/26] use of go url api

---
 transformer/transformers/ampruntimejs.go | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index 41656413c..26db70547 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -8,6 +8,7 @@ import (
 	"github.com/ampproject/amppackager/transformer/internal/htmlnode"
 	"golang.org/x/net/html/atom"
 	"golang.org/x/net/html"
+	"golang.org/x/net/html/url"
 )
 
 // AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
@@ -18,8 +19,15 @@ func AMPRuntimeJS(e *Context) error {
 			continue
 		}
 		if n.DataAtom == atom.Script {
-			if src, ok = htmlnode.FindAttribute(n, "", "src"); ok && strings.hasPrefix(src.Val, amphtml.AMPCacheRootURL) && strings.HasSuffix(src.Val, ".js"){
-				src.Val = strings.TrimSuffix(src.Val, ".js") + ".js&f=sxg"
+			if src, ok = htmlnode.FindAttribute(n, "", "src"); ok && strings.hasPrefix(src.Val, amphtml.AMPCacheRootURL){
+				u, _ = url.Parse(src.Val)
+				query, _ = url.ParseQuery(u.RawQuery)
+				path = u.Path
+				if strings.HasSuffix(path, ".js"){
+					query.Add("f", "sxg")
+					u.RawQuery = query.Encode()
+					src.Val = u.String()
+				}
 			}
 		} else {
 			continue

From 81dbcc802fb690be68200ad3c19ceef967144ae0 Mon Sep 17 00:00:00 2001
From: Derek Tse <xiexr151e@gmail.com>
Date: Mon, 10 Aug 2020 23:41:01 -0700
Subject: [PATCH 07/26] import error

---
 transformer/transformers/ampruntimejs.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index 26db70547..5a8018f85 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -3,12 +3,12 @@ package transformers
 import (
 	"regexp"
 	"strings"
+	"net/url"
 
 	"github.com/ampproject/amppackager/transformer/internal/amphtml"
 	"github.com/ampproject/amppackager/transformer/internal/htmlnode"
 	"golang.org/x/net/html/atom"
 	"golang.org/x/net/html"
-	"golang.org/x/net/html/url"
 )
 
 // AMPRuntimeJS rewrites the value of src in script nodes, where applicable.

From c69061c17a2ca957cc79e49e52454cab41affb99 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 16:25:56 -0700
Subject: [PATCH 08/26] compiler errors

---
 transformer/transformers/ampruntimejs.go      | 8 ++++----
 transformer/transformers/ampruntimejs_test.go | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index 400ed50ad..51f7a0cf2 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -1,13 +1,12 @@
 package transformers
 
 import (
-	"regexp"
 	"strings"
 
 	"github.com/ampproject/amppackager/transformer/internal/amphtml"
 	"github.com/ampproject/amppackager/transformer/internal/htmlnode"
-	"golang.org/x/net/html/atom"
 	"golang.org/x/net/html"
+	"golang.org/x/net/html/atom"
 )
 
 // AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
@@ -18,7 +17,8 @@ func AMPRuntimeJS(e *Context) error {
 			continue
 		}
 		if n.DataAtom == atom.Script {
-			if src, ok = htmlnode.FindAttribute(n, "", "src"); ok && strings.hasPrefix(src.Val, amphtml.AMPCacheRootURL) && strings.HasSuffix(src.Val, ".js"){
+			src, ok := htmlnode.FindAttribute(n, "", "src")
+			if ok && strings.HasPrefix(src.Val, amphtml.AMPCacheRootURL) && strings.HasSuffix(src.Val, ".js") {
 				src.Val = strings.TrimSuffix(src.Val, ".js") + ".sxg.js"
 			}
 		} else {
@@ -26,4 +26,4 @@ func AMPRuntimeJS(e *Context) error {
 		}
 	}
 	return nil
-}
\ No newline at end of file
+}
diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index 7c598f7db..2bb6ec66c 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -10,7 +10,7 @@ import (
 	"golang.org/x/net/html"
 )
 
-func TestStripJS(t *testing.T) {
+func TestAmpRuntimeJS(t *testing.T) {
 	tcs := []tt.TestCase{
 		{
 			Desc:     "no script node",
@@ -67,4 +67,4 @@ func TestStripJS(t *testing.T) {
 			t.Errorf("%s: Transform=\n%q\nwant=\n%q", tc.Desc, &input, &expected)
 		}
 	}
-}
\ No newline at end of file
+}

From 8a9d719ea89807f5085796570bbd66c572b4e951 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 16:33:51 -0700
Subject: [PATCH 09/26] compiler errors w/ url

---
 transformer/transformers/ampruntimejs.go      | 18 +++++++++---------
 transformer/transformers/ampruntimejs_test.go |  4 ++--
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index 5a8018f85..788433fb1 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -1,14 +1,13 @@
 package transformers
 
 import (
-	"regexp"
-	"strings"
 	"net/url"
+	"strings"
 
 	"github.com/ampproject/amppackager/transformer/internal/amphtml"
 	"github.com/ampproject/amppackager/transformer/internal/htmlnode"
-	"golang.org/x/net/html/atom"
 	"golang.org/x/net/html"
+	"golang.org/x/net/html/atom"
 )
 
 // AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
@@ -19,11 +18,12 @@ func AMPRuntimeJS(e *Context) error {
 			continue
 		}
 		if n.DataAtom == atom.Script {
-			if src, ok = htmlnode.FindAttribute(n, "", "src"); ok && strings.hasPrefix(src.Val, amphtml.AMPCacheRootURL){
-				u, _ = url.Parse(src.Val)
-				query, _ = url.ParseQuery(u.RawQuery)
-				path = u.Path
-				if strings.HasSuffix(path, ".js"){
+			src, ok := htmlnode.FindAttribute(n, "", "src")
+			if ok && strings.HasPrefix(src.Val, amphtml.AMPCacheRootURL) {
+				u, _ := url.Parse(src.Val)
+				query, _ := url.ParseQuery(u.RawQuery)
+				path := u.Path
+				if strings.HasSuffix(path, ".js") {
 					query.Add("f", "sxg")
 					u.RawQuery = query.Encode()
 					src.Val = u.String()
@@ -34,4 +34,4 @@ func AMPRuntimeJS(e *Context) error {
 		}
 	}
 	return nil
-}
\ No newline at end of file
+}
diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index eaa3a53c0..e3ad9af71 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -10,7 +10,7 @@ import (
 	"golang.org/x/net/html"
 )
 
-func TestStripJS(t *testing.T) {
+func TestAmpRuntimeJS(t *testing.T) {
 	tcs := []tt.TestCase{
 		{
 			Desc:     "no script node",
@@ -67,4 +67,4 @@ func TestStripJS(t *testing.T) {
 			t.Errorf("%s: Transform=\n%q\nwant=\n%q", tc.Desc, &input, &expected)
 		}
 	}
-}
\ No newline at end of file
+}

From 749ef8595a70d7a21d65391541b19738815d49fc Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 16:56:37 -0700
Subject: [PATCH 10/26] correction in test

---
 transformer/transformers/ampruntimejs_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index e3ad9af71..3c84185da 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -30,7 +30,7 @@ func TestAmpRuntimeJS(t *testing.T) {
 		{
 			Desc:     "transformation",
 			Input:    "<script async src=\"https://cdn.ampproject.org/v0.js\"></script>",
-			Expected: "<script async src=\"https://cdn.ampproject.org/v0.js&f=sxg\"></script>",
+			Expected: "<script async src=\"https://cdn.ampproject.org/v0.js?f=sxg\"></script>",
 		},
 	}
 

From 2c4570183e4384455dbcdbc213369f1b0f5b2a62 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 17:02:19 -0700
Subject: [PATCH 11/26] merge conflict

---
 transformer/transformers/ampruntimejs.go | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index 51f7a0cf2..788433fb1 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -1,6 +1,7 @@
 package transformers
 
 import (
+	"net/url"
 	"strings"
 
 	"github.com/ampproject/amppackager/transformer/internal/amphtml"
@@ -18,8 +19,15 @@ func AMPRuntimeJS(e *Context) error {
 		}
 		if n.DataAtom == atom.Script {
 			src, ok := htmlnode.FindAttribute(n, "", "src")
-			if ok && strings.HasPrefix(src.Val, amphtml.AMPCacheRootURL) && strings.HasSuffix(src.Val, ".js") {
-				src.Val = strings.TrimSuffix(src.Val, ".js") + ".sxg.js"
+			if ok && strings.HasPrefix(src.Val, amphtml.AMPCacheRootURL) {
+				u, _ := url.Parse(src.Val)
+				query, _ := url.ParseQuery(u.RawQuery)
+				path := u.Path
+				if strings.HasSuffix(path, ".js") {
+					query.Add("f", "sxg")
+					u.RawQuery = query.Encode()
+					src.Val = u.String()
+				}
 			}
 		} else {
 			continue

From 126558929a854c494611a736eec587b1d46e2653 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 17:03:02 -0700
Subject: [PATCH 12/26] correction to test

---
 transformer/transformers/ampruntimejs_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index 2bb6ec66c..3c84185da 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -30,7 +30,7 @@ func TestAmpRuntimeJS(t *testing.T) {
 		{
 			Desc:     "transformation",
 			Input:    "<script async src=\"https://cdn.ampproject.org/v0.js\"></script>",
-			Expected: "<script async src=\"https://cdn.ampproject.org/v0.sxg.js\"></script>",
+			Expected: "<script async src=\"https://cdn.ampproject.org/v0.js?f=sxg\"></script>",
 		},
 	}
 

From addc2865f3eec4ce63a978f433defbbafd677891 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 17:12:50 -0700
Subject: [PATCH 13/26] 14 transformers present

---
 transformer/transformer_test.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/transformer/transformer_test.go b/transformer/transformer_test.go
index 32ff55527..4c90cd7ab 100644
--- a/transformer/transformer_test.go
+++ b/transformer/transformer_test.go
@@ -6,9 +6,9 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/golang/protobuf/proto"
 	rpb "github.com/ampproject/amppackager/transformer/request"
 	"github.com/ampproject/amppackager/transformer/transformers"
+	"github.com/golang/protobuf/proto"
 	"github.com/google/go-cmp/cmp"
 )
 
@@ -27,7 +27,7 @@ func TestProcess(t *testing.T) {
 		config      rpb.Request_TransformersConfig
 		expectedLen int
 	}{
-		{rpb.Request_DEFAULT, 13},
+		{rpb.Request_DEFAULT, 14},
 		{rpb.Request_NONE, 0},
 		{rpb.Request_VALIDATION, 1},
 		{rpb.Request_CUSTOM, 0},

From 0a355d49b65b4ef67e0d9e54fc83de4a5bd7053d Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 17:49:16 -0700
Subject: [PATCH 14/26] minor semantic/syntactical changes

---
 transformer/transformer.go                    | 11 +++++------
 transformer/transformers/ampruntimejs.go      |  6 ++----
 transformer/transformers/ampruntimejs_test.go |  8 ++++----
 3 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/transformer/transformer.go b/transformer/transformer.go
index 969757123..a07be5b12 100644
--- a/transformer/transformer.go
+++ b/transformer/transformer.go
@@ -30,8 +30,8 @@ import (
 	rpb "github.com/ampproject/amppackager/transformer/request"
 	"github.com/ampproject/amppackager/transformer/transformers"
 	"github.com/pkg/errors"
-	"golang.org/x/net/html/atom"
 	"golang.org/x/net/html"
+	"golang.org/x/net/html/atom"
 )
 
 // Transformer functions must be added here in order to be passed in from
@@ -44,7 +44,7 @@ var transformerFunctionMap = map[string]func(*transformers.Context) error{
 	"absoluteurl":           transformers.AbsoluteURL,
 	"ampboilerplate":        transformers.AMPBoilerplate,
 	"ampruntimecss":         transformers.AMPRuntimeCSS,
-	"ampruntimejs":			 transformers.AMPRuntimeJS,
+	"ampruntimejs":          transformers.AMPRuntimeJS,
 	"linktag":               transformers.LinkTag,
 	"nodecleanup":           transformers.NodeCleanup,
 	"preloadimage":          transformers.PreloadImage,
@@ -92,7 +92,6 @@ var configMap = map[rpb.Request_TransformersConfig][]func(*transformers.Context)
 // from an unnecessary number of fetches.
 const maxPreloads = 20
 
-
 // Override for tests.
 var runTransformers = func(c *transformers.Context, fns []func(*transformers.Context) error) error {
 	// Invoke the configured transformers
@@ -226,11 +225,11 @@ func extractPreloads(dom *amphtml.DOM) []*rpb.Metadata_Preload {
 // amp-script without an explicit max-age. This is 1 day, to parallel the
 // security precautions put in place around service workers:
 // https://dev.chromium.org/Home/chromium-security/security-faq/service-worker-security-faq#TOC-Do-Service-Workers-live-forever-
-const defaultMaxAgeSeconds int32 = 86400  // number of seconds in a day
+const defaultMaxAgeSeconds int32 = 86400 // number of seconds in a day
 
 // maxMaxAgeSeconds is the max duration of an SXG, per
 // https://wicg.github.io/webpackage/draft-yasskin-http-origin-signed-responses.html#signature-validity.
-const maxMaxAgeSeconds int32 = 7*86400
+const maxMaxAgeSeconds int32 = 7 * 86400
 
 // computeMaxAgeSeconds returns the suggested max-age based on the presence of
 // any inline <amp-script> tags on the page; callers should min() the return
@@ -319,7 +318,7 @@ func Process(r *rpb.Request) (string, *rpb.Metadata, error) {
 		return "", nil, err
 	}
 	metadata := rpb.Metadata{
-		Preloads: extractPreloads(context.DOM),
+		Preloads:   extractPreloads(context.DOM),
 		MaxAgeSecs: computeMaxAgeSeconds(context.DOM),
 	}
 	return o.String(), &metadata, nil
diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index 788433fb1..e5d6a7a30 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -11,7 +11,7 @@ import (
 )
 
 // AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
-// If the value is of the form "*.js", replace it with "*.sxg.js".
+// If the value is of the form "*.js", replace it with "*.js?f=sxg".
 func AMPRuntimeJS(e *Context) error {
 	for n := e.DOM.RootNode; n != nil; n = htmlnode.Next(n) {
 		if n.Type != html.ElementNode {
@@ -24,13 +24,11 @@ func AMPRuntimeJS(e *Context) error {
 				query, _ := url.ParseQuery(u.RawQuery)
 				path := u.Path
 				if strings.HasSuffix(path, ".js") {
-					query.Add("f", "sxg")
+					query.Set("f", "sxg")
 					u.RawQuery = query.Encode()
 					src.Val = u.String()
 				}
 			}
-		} else {
-			continue
 		}
 	}
 	return nil
diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index 3c84185da..859e582ed 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -24,13 +24,13 @@ func TestAmpRuntimeJS(t *testing.T) {
 		},
 		{
 			Desc:     "no suffix",
-			Input:    "<script src=\"https://cdn.ampproject.org\"/>",
-			Expected: "<script src=\"https://cdn.ampproject.org\"/>",
+			Input:    `<script src="https://cdn.ampproject.org"/>`,
+			Expected: `<script src="https://cdn.ampproject.org"/>`,
 		},
 		{
 			Desc:     "transformation",
-			Input:    "<script async src=\"https://cdn.ampproject.org/v0.js\"></script>",
-			Expected: "<script async src=\"https://cdn.ampproject.org/v0.js?f=sxg\"></script>",
+			Input:    `<script async src="https://cdn.ampproject.org/v0.js"></script>`,
+			Expected: `<script async src="https://cdn.ampproject.org/v0.js?f=sxg"></script>`,
 		},
 	}
 

From 95cca8838f0d33d3f8e7e756f451411444088d00 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 17:53:11 -0700
Subject: [PATCH 15/26] headnode

---
 transformer/transformers/ampruntimejs.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index e5d6a7a30..071b7e3e1 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -13,7 +13,7 @@ import (
 // AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
 // If the value is of the form "*.js", replace it with "*.js?f=sxg".
 func AMPRuntimeJS(e *Context) error {
-	for n := e.DOM.RootNode; n != nil; n = htmlnode.Next(n) {
+	for n := e.DOM.HeadNode; n != nil; n = htmlnode.Next(n) {
 		if n.Type != html.ElementNode {
 			continue
 		}

From fc36393f48fd2623257476e635b030571b77b0f9 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 17:55:15 -0700
Subject: [PATCH 16/26] format

---
 transformer/transformers/ampruntimejs.go      |  70 ++++-----
 transformer/transformers/ampruntimejs_test.go | 140 +++++++++---------
 2 files changed, 105 insertions(+), 105 deletions(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index 071b7e3e1..354db1e47 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -1,35 +1,35 @@
-package transformers
-
-import (
-	"net/url"
-	"strings"
-
-	"github.com/ampproject/amppackager/transformer/internal/amphtml"
-	"github.com/ampproject/amppackager/transformer/internal/htmlnode"
-	"golang.org/x/net/html"
-	"golang.org/x/net/html/atom"
-)
-
-// AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
-// If the value is of the form "*.js", replace it with "*.js?f=sxg".
-func AMPRuntimeJS(e *Context) error {
-	for n := e.DOM.HeadNode; n != nil; n = htmlnode.Next(n) {
-		if n.Type != html.ElementNode {
-			continue
-		}
-		if n.DataAtom == atom.Script {
-			src, ok := htmlnode.FindAttribute(n, "", "src")
-			if ok && strings.HasPrefix(src.Val, amphtml.AMPCacheRootURL) {
-				u, _ := url.Parse(src.Val)
-				query, _ := url.ParseQuery(u.RawQuery)
-				path := u.Path
-				if strings.HasSuffix(path, ".js") {
-					query.Set("f", "sxg")
-					u.RawQuery = query.Encode()
-					src.Val = u.String()
-				}
-			}
-		}
-	}
-	return nil
-}
+package transformers
+
+import (
+	"net/url"
+	"strings"
+
+	"github.com/ampproject/amppackager/transformer/internal/amphtml"
+	"github.com/ampproject/amppackager/transformer/internal/htmlnode"
+	"golang.org/x/net/html"
+	"golang.org/x/net/html/atom"
+)
+
+// AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
+// If the value is of the form "*.js", replace it with "*.js?f=sxg".
+func AMPRuntimeJS(e *Context) error {
+	for n := e.DOM.HeadNode; n != nil; n = htmlnode.Next(n) {
+		if n.Type != html.ElementNode {
+			continue
+		}
+		if n.DataAtom == atom.Script {
+			src, ok := htmlnode.FindAttribute(n, "", "src")
+			if ok && strings.HasPrefix(src.Val, amphtml.AMPCacheRootURL) {
+				u, _ := url.Parse(src.Val)
+				query, _ := url.ParseQuery(u.RawQuery)
+				path := u.Path
+				if strings.HasSuffix(path, ".js") {
+					query.Set("f", "sxg")
+					u.RawQuery = query.Encode()
+					src.Val = u.String()
+				}
+			}
+		}
+	}
+	return nil
+}
diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index 859e582ed..c429f64dc 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -1,70 +1,70 @@
-package transformers_test
-
-import (
-	"strings"
-	"testing"
-
-	"github.com/ampproject/amppackager/transformer/internal/amphtml"
-	tt "github.com/ampproject/amppackager/transformer/internal/testing"
-	"github.com/ampproject/amppackager/transformer/transformers"
-	"golang.org/x/net/html"
-)
-
-func TestAmpRuntimeJS(t *testing.T) {
-	tcs := []tt.TestCase{
-		{
-			Desc:     "no script node",
-			Input:    "<head></head><body></body>",
-			Expected: "<head></head><body></body>",
-		},
-		{
-			Desc:     "no prefix",
-			Input:    "<script src=main.js/>",
-			Expected: "<script src=main.js/>",
-		},
-		{
-			Desc:     "no suffix",
-			Input:    `<script src="https://cdn.ampproject.org"/>`,
-			Expected: `<script src="https://cdn.ampproject.org"/>`,
-		},
-		{
-			Desc:     "transformation",
-			Input:    `<script async src="https://cdn.ampproject.org/v0.js"></script>`,
-			Expected: `<script async src="https://cdn.ampproject.org/v0.js?f=sxg"></script>`,
-		},
-	}
-
-	for _, tc := range tcs {
-		inputDoc, err := html.Parse(strings.NewReader(tc.Input))
-		if err != nil {
-			t.Errorf("%s: html.Parse failed %q", tc.Input, err)
-			continue
-		}
-		inputDOM, err := amphtml.NewDOM(inputDoc)
-		if err != nil {
-			t.Errorf("%s\namphtml.NewDOM for %s failed %q", tc.Desc, tc.Input, err)
-			continue
-		}
-		transformers.AMPRuntimeJS(&transformers.Context{DOM: inputDOM})
-		var input strings.Builder
-		if err := html.Render(&input, inputDoc); err != nil {
-			t.Errorf("%s: html.Render failed %q", tc.Input, err)
-			continue
-		}
-
-		expectedDoc, err := html.Parse(strings.NewReader(tc.Expected))
-		if err != nil {
-			t.Errorf("%s: html.Parse failed %q", tc.Expected, err)
-			continue
-		}
-		var expected strings.Builder
-		err = html.Render(&expected, expectedDoc)
-		if err != nil {
-			t.Errorf("%s: html.Render failed %q", tc.Expected, err)
-			continue
-		}
-		if input.String() != expected.String() {
-			t.Errorf("%s: Transform=\n%q\nwant=\n%q", tc.Desc, &input, &expected)
-		}
-	}
-}
+package transformers_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/ampproject/amppackager/transformer/internal/amphtml"
+	tt "github.com/ampproject/amppackager/transformer/internal/testing"
+	"github.com/ampproject/amppackager/transformer/transformers"
+	"golang.org/x/net/html"
+)
+
+func TestAmpRuntimeJS(t *testing.T) {
+	tcs := []tt.TestCase{
+		{
+			Desc:     "no script node",
+			Input:    "<head></head><body></body>",
+			Expected: "<head></head><body></body>",
+		},
+		{
+			Desc:     "no prefix",
+			Input:    "<script src=main.js/>",
+			Expected: "<script src=main.js/>",
+		},
+		{
+			Desc:     "no suffix",
+			Input:    `<script src="https://cdn.ampproject.org"/>`,
+			Expected: `<script src="https://cdn.ampproject.org"/>`,
+		},
+		{
+			Desc:     "transformation",
+			Input:    `<script async src="https://cdn.ampproject.org/v0.js"></script>`,
+			Expected: `<script async src="https://cdn.ampproject.org/v0.js?f=sxg"></script>`,
+		},
+	}
+
+	for _, tc := range tcs {
+		inputDoc, err := html.Parse(strings.NewReader(tc.Input))
+		if err != nil {
+			t.Errorf("%s: html.Parse failed %q", tc.Input, err)
+			continue
+		}
+		inputDOM, err := amphtml.NewDOM(inputDoc)
+		if err != nil {
+			t.Errorf("%s\namphtml.NewDOM for %s failed %q", tc.Desc, tc.Input, err)
+			continue
+		}
+		transformers.AMPRuntimeJS(&transformers.Context{DOM: inputDOM})
+		var input strings.Builder
+		if err := html.Render(&input, inputDoc); err != nil {
+			t.Errorf("%s: html.Render failed %q", tc.Input, err)
+			continue
+		}
+
+		expectedDoc, err := html.Parse(strings.NewReader(tc.Expected))
+		if err != nil {
+			t.Errorf("%s: html.Parse failed %q", tc.Expected, err)
+			continue
+		}
+		var expected strings.Builder
+		err = html.Render(&expected, expectedDoc)
+		if err != nil {
+			t.Errorf("%s: html.Render failed %q", tc.Expected, err)
+			continue
+		}
+		if input.String() != expected.String() {
+			t.Errorf("%s: Transform=\n%q\nwant=\n%q", tc.Desc, &input, &expected)
+		}
+	}
+}

From 8bcdf4542c00c953688b4f40babcc27c63ed991d Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 19:34:28 -0700
Subject: [PATCH 17/26] next sibling

---
 transformer/transformers/ampruntimejs.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index 354db1e47..fa89e6372 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -13,7 +13,7 @@ import (
 // AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
 // If the value is of the form "*.js", replace it with "*.js?f=sxg".
 func AMPRuntimeJS(e *Context) error {
-	for n := e.DOM.HeadNode; n != nil; n = htmlnode.Next(n) {
+	for n := e.DOM.HeadNode; n != nil; n = n.NextSibling {
 		if n.Type != html.ElementNode {
 			continue
 		}

From 79c2296cb49fc4e2c84b219599e782f38a40c89b Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 19:38:28 -0700
Subject: [PATCH 18/26] additional test

---
 transformer/transformers/ampruntimejs_test.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index c429f64dc..2ea0625b2 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -32,6 +32,11 @@ func TestAmpRuntimeJS(t *testing.T) {
 			Input:    `<script async src="https://cdn.ampproject.org/v0.js"></script>`,
 			Expected: `<script async src="https://cdn.ampproject.org/v0.js?f=sxg"></script>`,
 		},
+		{
+			Desc:     "transform on two scripts",
+			Input:    `<head><script async src="https://cdn.ampproject.org/foo.js"></script><script async src="https://cdn.ampproject.org/bar.js"></script></head>`,
+			Expected: `<head><script async src="https://cdn.ampproject.org/foo.js?f=sxg"></script><script async src="https://cdn.ampproject.org/bar.js?f=sxg"></script></head>`,
+		},
 	}
 
 	for _, tc := range tcs {

From e9295bf471130e139bd3eaa7b16661a23073dd77 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 19:44:53 -0700
Subject: [PATCH 19/26] revert next

---
 transformer/transformers/ampruntimejs.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index fa89e6372..354db1e47 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -13,7 +13,7 @@ import (
 // AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
 // If the value is of the form "*.js", replace it with "*.js?f=sxg".
 func AMPRuntimeJS(e *Context) error {
-	for n := e.DOM.HeadNode; n != nil; n = n.NextSibling {
+	for n := e.DOM.HeadNode; n != nil; n = htmlnode.Next(n) {
 		if n.Type != html.ElementNode {
 			continue
 		}

From ddb10fa4cc6219c0c6a779fe5734e80744bf843a Mon Sep 17 00:00:00 2001
From: "Derek X. R. Tse" <arrestrose@gmail.com>
Date: Wed, 12 Aug 2020 19:54:46 -0700
Subject: [PATCH 20/26] Rearranged import name?

---
 transformer/transformer_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/transformer/transformer_test.go b/transformer/transformer_test.go
index 4c90cd7ab..0af4046fa 100644
--- a/transformer/transformer_test.go
+++ b/transformer/transformer_test.go
@@ -6,9 +6,9 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/golang/protobuf/proto"
 	rpb "github.com/ampproject/amppackager/transformer/request"
 	"github.com/ampproject/amppackager/transformer/transformers"
-	"github.com/golang/protobuf/proto"
 	"github.com/google/go-cmp/cmp"
 )
 

From 74ecad220445964e5ad5ebb0e6eae035b9546a98 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Wed, 12 Aug 2020 21:41:15 -0700
Subject: [PATCH 21/26] wrap everything in head

---
 transformer/transformers/ampruntimejs.go      |  2 +-
 transformer/transformers/ampruntimejs_test.go | 12 ++++++------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index 354db1e47..fa89e6372 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -13,7 +13,7 @@ import (
 // AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
 // If the value is of the form "*.js", replace it with "*.js?f=sxg".
 func AMPRuntimeJS(e *Context) error {
-	for n := e.DOM.HeadNode; n != nil; n = htmlnode.Next(n) {
+	for n := e.DOM.HeadNode; n != nil; n = n.NextSibling {
 		if n.Type != html.ElementNode {
 			continue
 		}
diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index 2ea0625b2..bbdb2801b 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -19,18 +19,18 @@ func TestAmpRuntimeJS(t *testing.T) {
 		},
 		{
 			Desc:     "no prefix",
-			Input:    "<script src=main.js/>",
-			Expected: "<script src=main.js/>",
+			Input:    "<head><script src=main.js/></head>",
+			Expected: "<head><script src=main.js/></head>",
 		},
 		{
 			Desc:     "no suffix",
-			Input:    `<script src="https://cdn.ampproject.org"/>`,
-			Expected: `<script src="https://cdn.ampproject.org"/>`,
+			Input:    `<head><script src="https://cdn.ampproject.org"/></head>`,
+			Expected: `<head><script src="https://cdn.ampproject.org"/></head>`,
 		},
 		{
 			Desc:     "transformation",
-			Input:    `<script async src="https://cdn.ampproject.org/v0.js"></script>`,
-			Expected: `<script async src="https://cdn.ampproject.org/v0.js?f=sxg"></script>`,
+			Input:    `<head><script async src="https://cdn.ampproject.org/v0.js"></script></head>`,
+			Expected: `<head><script async src="https://cdn.ampproject.org/v0.js?f=sxg"></script></head>`,
 		},
 		{
 			Desc:     "transform on two scripts",

From 82b4ad3a170c57683a52e4627763a4536e8b9fa8 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Thu, 13 Aug 2020 12:31:17 -0700
Subject: [PATCH 22/26] firstchild

---
 transformer/transformers/ampruntimejs.go      | 2 +-
 transformer/transformers/ampruntimejs_test.go | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index fa89e6372..d4db3bee6 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -13,7 +13,7 @@ import (
 // AMPRuntimeJS rewrites the value of src in script nodes, where applicable.
 // If the value is of the form "*.js", replace it with "*.js?f=sxg".
 func AMPRuntimeJS(e *Context) error {
-	for n := e.DOM.HeadNode; n != nil; n = n.NextSibling {
+	for n := e.DOM.HeadNode.FirstChild; n != nil; n = n.NextSibling {
 		if n.Type != html.ElementNode {
 			continue
 		}
diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index bbdb2801b..c56a2fdb9 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -37,6 +37,11 @@ func TestAmpRuntimeJS(t *testing.T) {
 			Input:    `<head><script async src="https://cdn.ampproject.org/foo.js"></script><script async src="https://cdn.ampproject.org/bar.js"></script></head>`,
 			Expected: `<head><script async src="https://cdn.ampproject.org/foo.js?f=sxg"></script><script async src="https://cdn.ampproject.org/bar.js?f=sxg"></script></head>`,
 		},
+		{
+			Desc:     "skip one, transform one",
+			Input:    `<head><script async src="https://cdn.ampproject.org/"></script><script async src="https://cdn.ampproject.org/bar.js"></script></head>`,
+			Expected: `<head><script async src="https://cdn.ampproject.org/"></script><script async src="https://cdn.ampproject.org/bar.js?f=sxg"></script></head>`,
+		},
 	}
 
 	for _, tc := range tcs {

From dc4c310f94e09bc26d8f59d20b39901067ed5f4d Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Sat, 15 Aug 2020 00:23:50 -0700
Subject: [PATCH 23/26] various suggestions

---
 transformer/transformers/ampruntimejs.go      | 10 +++++-----
 transformer/transformers/ampruntimejs_test.go | 20 +++++++++++++++++++
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index d4db3bee6..be0a262a5 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -14,13 +14,13 @@ import (
 // If the value is of the form "*.js", replace it with "*.js?f=sxg".
 func AMPRuntimeJS(e *Context) error {
 	for n := e.DOM.HeadNode.FirstChild; n != nil; n = n.NextSibling {
-		if n.Type != html.ElementNode {
-			continue
-		}
-		if n.DataAtom == atom.Script {
+		if n.Type == html.ElementNode && n.DataAtom == atom.Script {
 			src, ok := htmlnode.FindAttribute(n, "", "src")
 			if ok && strings.HasPrefix(src.Val, amphtml.AMPCacheRootURL) {
-				u, _ := url.Parse(src.Val)
+				u, err := url.Parse(src.Val)
+				if err != nil {
+					continue
+				}
 				query, _ := url.ParseQuery(u.RawQuery)
 				path := u.Path
 				if strings.HasSuffix(path, ".js") {
diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index c56a2fdb9..7a7ad0592 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -42,6 +42,26 @@ func TestAmpRuntimeJS(t *testing.T) {
 			Input:    `<head><script async src="https://cdn.ampproject.org/"></script><script async src="https://cdn.ampproject.org/bar.js"></script></head>`,
 			Expected: `<head><script async src="https://cdn.ampproject.org/"></script><script async src="https://cdn.ampproject.org/bar.js?f=sxg"></script></head>`,
 		},
+		{
+			Desc:     "additional params exist",
+			Input:    `<head><script async src="https://cdn.ampproject.org/v0.js?optin=beta"></script></head>`,
+			Expected: `<head><script async src="https://cdn.ampproject.org/v0.js?optin=beta&f=sxg"></script></head>`,
+		},
+		{
+			Desc:     "existing f param",
+			Input:    `<head><script async src="https://cdn.ampproject.org/v0.js?f=foo"></script></head>`,
+			Expected: `<head><script async src="https://cdn.ampproject.org/v0.js?f=sxg"></script></head>`,
+		},
+		{
+			Desc:     "parsing bug",
+			Input:    `<head><script async src="https://cdn.ampproject.org/v0.js?x=%"></script></head>`,
+			Expected: `<head><script async src="https://cdn.ampproject.org/v0.js?x=%"></script></head>`,
+		},
+		{
+			Desc:     "parsing bug",
+			Input:    `<head><script async src="https://cdn.ampproject.org/v0.js%%"></script></head>`,
+			Expected: `<head><script async src="https://cdn.ampproject.org/v0.js%%"></script></head>`,
+		}
 	}
 
 	for _, tc := range tcs {

From 7eb243867359818a66829db73b6d613442afbc98 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Sat, 15 Aug 2020 00:35:28 -0700
Subject: [PATCH 24/26] rename test

---
 transformer/transformers/ampruntimejs_test.go | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index 7a7ad0592..afffc2d1e 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -53,15 +53,15 @@ func TestAmpRuntimeJS(t *testing.T) {
 			Expected: `<head><script async src="https://cdn.ampproject.org/v0.js?f=sxg"></script></head>`,
 		},
 		{
-			Desc:     "parsing bug",
+			Desc:     "url escape parsing bug in query param",
 			Input:    `<head><script async src="https://cdn.ampproject.org/v0.js?x=%"></script></head>`,
 			Expected: `<head><script async src="https://cdn.ampproject.org/v0.js?x=%"></script></head>`,
 		},
 		{
-			Desc:     "parsing bug",
+			Desc:     "url escape parsing bug",
 			Input:    `<head><script async src="https://cdn.ampproject.org/v0.js%%"></script></head>`,
 			Expected: `<head><script async src="https://cdn.ampproject.org/v0.js%%"></script></head>`,
-		}
+		},
 	}
 
 	for _, tc := range tcs {

From adcfd26a2a53b49534b9cbebff6138b847e8b287 Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Sat, 15 Aug 2020 00:49:33 -0700
Subject: [PATCH 25/26] more error

---
 transformer/transformers/ampruntimejs.go | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/transformer/transformers/ampruntimejs.go b/transformer/transformers/ampruntimejs.go
index be0a262a5..4046c244e 100644
--- a/transformer/transformers/ampruntimejs.go
+++ b/transformer/transformers/ampruntimejs.go
@@ -17,11 +17,14 @@ func AMPRuntimeJS(e *Context) error {
 		if n.Type == html.ElementNode && n.DataAtom == atom.Script {
 			src, ok := htmlnode.FindAttribute(n, "", "src")
 			if ok && strings.HasPrefix(src.Val, amphtml.AMPCacheRootURL) {
-				u, err := url.Parse(src.Val)
-				if err != nil {
+				u, uerr := url.Parse(src.Val)
+				if uerr != nil {
+					continue
+				}
+				query, queryerr := url.ParseQuery(u.RawQuery)
+				if queryerr != nil {
 					continue
 				}
-				query, _ := url.ParseQuery(u.RawQuery)
 				path := u.Path
 				if strings.HasSuffix(path, ".js") {
 					query.Set("f", "sxg")

From 2eefaba13c48ce5fbe6a4920b412ea3c8f1c702d Mon Sep 17 00:00:00 2001
From: Derek Tse <derektse@google.com>
Date: Sat, 15 Aug 2020 00:57:26 -0700
Subject: [PATCH 26/26] test fix

---
 transformer/transformers/ampruntimejs_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/transformer/transformers/ampruntimejs_test.go b/transformer/transformers/ampruntimejs_test.go
index afffc2d1e..88bee8bec 100644
--- a/transformer/transformers/ampruntimejs_test.go
+++ b/transformer/transformers/ampruntimejs_test.go
@@ -45,7 +45,7 @@ func TestAmpRuntimeJS(t *testing.T) {
 		{
 			Desc:     "additional params exist",
 			Input:    `<head><script async src="https://cdn.ampproject.org/v0.js?optin=beta"></script></head>`,
-			Expected: `<head><script async src="https://cdn.ampproject.org/v0.js?optin=beta&f=sxg"></script></head>`,
+			Expected: `<head><script async src="https://cdn.ampproject.org/v0.js?f=sxg&optin=beta"></script></head>`,
 		},
 		{
 			Desc:     "existing f param",